How the Human Immune System Works questions

Which of the following first line of defense means failed to prevent the coronavirus from entering the body?

1. A Skin and sweat
2. B Mucus and cilia
3. C Tears and earwax
4. D HCl and saliva

Which immune structure has an exocrine secretion inside the body?

1. A Salivary glands
2. B Sweat glands
3. C Thymus gland
4. D Lacrimal gland

What type of glands are the lacrimal glands in humans?

1. A Duct glands with an exocrine secretion outside the body
2. B Mixed
3. C Duct glands with an exocrine secretion inside the body
4. D Endocrine

Which of the following choices expresses the means of the first line of defense in the body?

1. A Skin / tears / HCl acid / white blood cells
2. B Tears / mucous membranes / HCl acid / basophils
3. C Skin / tears / mucous membranes / HCl acid
4. D Tears / mast cells / white blood cells / HCl acid

Which of the following statements is correct about the immune enzymes of saliva?

1. A They activate complement proteins
2. B They break down the nucleic acids of bacteria
3. C They break down bacterial cell walls
4. D They are secreted from ductless glands

Which of the following properties makes mucus play an immune role?

1. A It kills all microbes
2. B It activates immune cells
3. C It is an acidic substance
4. D It is a sticky substance

What is the name of the substance responsible for moving some phagocytic cells and natural killer cells from the blood plasma to the infected tissue?

1. A Interleukins
2. B Histamine
3. C Interferons
4. D Globulins

An increase in the hydrogen ion concentration in human urine gives the urinary bladder and the urethra .......... immunity.

1. A natural
2. B specific
3. C acquired humoral
4. D acquired cell-mediated

How do ciliated cells work in the first line of defense in humans?

1. A They secrete mucus to protect the lungs from pathogens
2. B They protect the female reproductive system from diseases
3. C They expel dust and pathogens to prevent them from entering the lungs
4. D They secrete HCl acid to destroy pathogens

Which of the following substances is foreign to the body?

1. A Interferons
2. B Antigens
3. C Immunoglobulins
4. D Immune receptors

Which of the following is one of the mechanisms of innate immunity?

1. A Neutrophils engulfing the pathogen
2. B Formation of memory cells
3. C Neutralizing toxins by antibodies
4. D Division of B cells

Which of the following applies to natural immunity?

1. A Some of its means work the moment the microbe reaches the body tissues
2. B It depends on previous exposure to the same pathogen
3. C It depends on recognizing the antigen
4. D It is found only in vertebrates and humans

From the following figure, what is the type of the cell and the type of the immune response against the pathogens?

1. A B lymphocyte – producing antibodies
2. B Macrophage – swallowing pathogens
3. C Neutrophil – engulfing bacteria
4. D Mast cell – secreting histamine

How many substances do T cells produce during the activity of non-specific immunity?

1. A Zero
2. B 1
3. C 3
4. D 5

Which of the following does not apply to non-specific immune defenses?

1. A They include physical and chemical barriers
2. B They include natural killer cells and phagocytes
3. C They include inflammatory responses
4. D They require the presence of an antigen to happen

From the opposite figure, what does cell (X) represent?

1. A Macrophage
2. B Mast cell
3. C Memory B cell
4. D Helper T cell

Which of the following statements is correct?

1. A All white blood cells are produced in the bone marrow
2. B Mast cells are active in the blood and body tissues
3. C The inflammatory response belongs to the first line of defense
4. D All blood cells leave the bone marrow fully mature

What happens when bacteria enter the body through a small wound in the skin?

1. A The flow of red blood cells to the wound decreases
2. B All body cells secrete interferons
3. C Cytotoxic T cells are activated
4. D The permeability of small blood vessels to plasma increases in the infected part

Which of the following statements is not correct?

1. A Antibodies are relatively large molecules
2. B Histamine increases the permeability of antibodies into infected cells
3. C The antibody IgG consists of 4 protein chains
4. D Antibodies contain peptide bonds

What chemical substance is secreted by some types of white blood cells and causes the temperature of the infected part of the body to rise?

1. A Perforin
2. B Histamine
3. C Antibodies
4. D Cytokines

The following figures show the steps of the inflammatory response. Which of the following choices represents the correct order of these steps?

1. A (1) → (2) → (3)
2. B (3) → (2) → (1)
3. C (2) → (1) → (3)
4. D (2) → (3) → (1)

Which of the following is not related to the secretion of histamine?

1. A Dilation of blood vessels
2. B Allowing B cells to move towards the site of infection
3. C Increasing the permeability of small blood vessels
4. D Swelling and redness at the site of infection

The inflammatory response is characterized by being ..........

1. A fast and specific
2. B fast and non-specific
3. C slow and specific
4. D slow and non-specific

Which of the following cells does not work in the second line of defense?

1. A Mast cells
2. B Macrophages
3. C B cells
4. D Natural killer cells

The opposite figure represents some blood components in humans:
Which of the following cells secretes histamine?

1. A X
2. B Y
3. C Z
4. D L

The opposite figure represents some blood components in humans:
Which of the following cells differentiate, some in the thymus gland and others in the red bone marrow?

1. A X
2. B Y
3. C Z
4. D L

The opposite figure represents some blood components in humans:
Which of the following represents an eosinophil (acidophil) white blood cell?

1. A X
2. B Y
3. C Z
4. D L

Which of the following is not one of the aims of the inflammatory response?

1. A Preventing the microbe from reaching the blood
2. B Killing the pathogenic organisms
3. C Limiting the reproduction of the pathogenic microbe
4. D Identifying the type of the microbe

Which of the following responses correctly represents non-specific immunity?

1. A A
2. B B
3. C C
4. D D

What is the cause of the response shown in the two opposite figures?

1. A The body trying to prevent the pathogen from penetrating the body surface
2. B Secretion of chemokines to attract phagocytes
3. C The secretory activity of basophils and mast cells
4. D A rise in the osmotic pressure of the blood

Which of the following represents both the cells and the immune substances used by the body during the early stages of the inflammatory response?

1. A Phagocytes and cytokines
2. B Mast cells and interferons
3. C Basophils and histamine
4. D Lymphocytes and interferons

Which of the following graphs shows the amount of blood flowing in the blood vessels of a tissue when an inflammatory response happens?

1. A A
2. B B
3. C C
4. D D

The following choices show stages of the inflammatory response. Which of them, if it does not happen, prevents all the other stages from being completed?

1. A Leakage of plasma into the infected area
2. B Increase in the permeability of small blood vessels
3. C Increase in the number of phagocytes in the infected area
4. D Secretion of histamine

Which of the following chemical substances increases at the wound site during the first stage of the inflammatory response?

1. A Chemokines
2. B Antibodies
3. C Interferons
4. D Complement proteins

Some people get inflammation of the mucous membranes lining the nose when they breathe air polluted with dust, so the doctor prescribes a drug against ..........

1. A lymphokine
2. B histamine
3. C interleukin
4. D perforin

Where and when are specific lymphocytes activated?

1. A The blood – in the presence of the microbe
2. B The thymus gland – in the presence of MHC protein
3. C The bone marrow – in the presence of the antigen
4. D The lymph nodes – in the presence of lymphokines

Which of the following is one of the body's responses during specific immunity?

1. A Production of chemokines
2. B Production of antibodies
3. C Movement of the cilia of the trachea
4. D Inflammation

What is the effect of a defect in the immune receptor on the surface of helper T cells?

1. A No binding to the antigens of viruses in the blood
2. B The inflammatory response stops
3. C No binding with the complex of the antigen and the MHC protein
4. D Secretion of interferons stops

What happens after helper T cells recognize the antigen displayed on the surface of phagocytes?

1. A They divide and their numbers multiply
2. B They move from the thymus gland to the blood
3. C They release interferons
4. D They release antibodies

Which of the following does the function of the MHC protein depend on?

1. A The type of the microbe
2. B The presence of an immune receptor on the membrane of TH cells
3. C Displaying the antigen on the nuclear membrane
4. D Binding with the antigen

Which of the following immune cells is specific?

1. A A
2. B B
3. C C
4. D D

From the opposite figure, what do the lines of defense (X), (Y) and (Z) represent, respectively, in the human body?

1. A Second / first / third
2. B First / second / third
3. C First / third / second
4. D Third / second / first

Which of the following is one of the features of adaptive immunity?

1. A Redness and swelling at the site of infection
2. B Secretion of inflammation-causing substances
3. C Secretion of cytokines
4. D Increase of mucus in the respiratory system

What is the main role of acquired humoral immunity?

1. A Protecting the body from pathogens in the body fluids
2. B Preventing the microbe from entering the body
3. C Rejecting transplanted organs
4. D Protecting the body from cancer cells

From the opposite figure, which of the following choices is correct about (X), (Y) and (Z)?

1. A X: NK cells / Y: phagocytes / Z: mast cells
2. B X: NK cells / Y: mast cells / Z: B cells
3. C X: phagocytes / Y: NK cells / Z: mast cells
4. D X: mast cells / Y: phagocytes / Z: T cells

The following stages happen when the human immune system meets a pathogen:
X: The pathogen is destroyed.
Y: Lymphocytes secrete antibodies.
Z: Antigens bind to the receptors of lymphocytes.
L: Memory cells are formed.
What is the correct order of these stages?

1. A Z → L → X → Y
2. B Z → Y → L → X
3. C Y → L → Z → X
4. D Z → L → Y → X

Which of the following choices is correct?

1. A Cell: mast / secreted substance: histamine / line of defense: first
2. B Cell: TH / secreted substance: interleukins / line of defense: second
3. C Cell: TC / secreted substance: lymphotoxins / line of defense: third
4. D Cell: NK / secreted substance: cytokines / line of defense: second

Which of the following statements correctly describes stage (X) in the opposite figure?

1. A Displaying the antigen on the surface of the phagocyte
2. B Lysosome enzymes breaking the antigen into pieces
3. C Binding of the antigen with the MHC protein
4. D The cell releasing interferons

Which of the following pairs are similar in that both stimulate certain cells?

1. A Lymphokines and complement proteins
2. B Cytokines and interferons
3. C Complement proteins and interferons
4. D Antibodies and lymphokines

Which cells do not take part in the work of the third line of defense?

1. A Mast cells
2. B B cells
3. C Helper T cells
4. D Suppressor T cells

What substance acts as a mediator between two similar body cells if one of them is infected by a virus?

1. A Cytokines
2. B Lymphokines
3. C Interferons
4. D Lymphotoxins

Which of the following statements correctly describes the opposite graph?

1. A (X) and (Y) represent the first line of defense
2. B (Y) represents innate immunity, (X) represents acquired immunity
3. C (Y) represents humoral immunity, (X) represents cell-mediated immunity
4. D (X) represents an inflammatory response, (Y) represents an antibody response

Genes in the nuclei of cancer cells are activated, leading to their destruction; this is known as programmed cell death. Which of the following is responsible for that?

1. A Lymphotoxins
2. B Perforin
3. C Interferons
4. D Antibodies

During the immune response, which of the following lymphocytes produces substances that tear the cell membrane of cancer cells?

1. A B cells
2. B Plasma B cells
3. C Killer T cells
4. D Suppressor T cells

A person took a chemical substance that increased the rate of division of liver cells without the body's control, which increased the size of the liver. Which of the following cells are expected to increase in number in this case?

1. A Memory B cells and suppressor T cells
2. B Natural killer cells and suppressor T cells
3. C Plasma B cells and killer T cells
4. D Cytotoxic T cells and natural killer cells

What substances activate B cells?

1. A Interleukins only
2. B Cytokines only
3. C Complement proteins and interleukins
4. D Interleukins and cytokines

From the opposite figure, which of the following is a component of the immune system?

1. A (X) only
2. B (X), (Y)
3. C (Y) only
4. D (X), (Z)

Which of the following can explain the importance of the antigen on the surface of bacteria for the immune system?

1. A Antibodies bind to it
2. B Infected cells are destroyed
3. C TS recognize it
4. D Plasma (B) cells bind to it

Which substance depends in its work on the activity of helper T cells (TH) indirectly?

1. A Interleukins
2. B Histamine
3. C Complement proteins
4. D Cytokines

The opposite figure shows a neutrophil white blood cell while doing its immune role in the body. Study it, then answer:
What is the process shown in the figure called?

1. A Engulfing
2. B Feeding
3. C Agglutination
4. D Engulfing and digestion

The opposite figure shows a neutrophil white blood cell while doing its immune role in the body. Study it, then answer:
What is the importance of structure (X)?

1. A It prevents the pathogen from entering the white blood cell
2. B It binds to antibodies
3. C It displays the complex of the antigen and the MHC protein
4. D It binds to the pathogen

Which of the following cells does not increase in number during a viral infection?

1. A TS
2. B TH
3. C TC
4. D Plasma B

Comparing the speed of the innate immune response with the acquired one, we find that the acquired immune response is ..........

1. A faster
2. B slower
3. C the same speed
4. D sometimes faster and sometimes slower

From the opposite figure, which of the following does structure (X) bind to?

1. A The antigen
2. B The antibody
3. C The MHC protein
4. D The antigen bound to the MHC protein

Which of the following chemical substances increases at the same time as plasma (B) cells increase?

1. A Lymphokines
2. B Perforin
3. C Interferons
4. D Complement proteins

Which of the following statements is not correct?

1. A TS cells are active during the infection
2. B The activity of TH cells is affected by TS cells
3. C The activity of TS cells is affected by TH cells
4. D The secretions of TS cells affect B cells

Which of the following graphs expresses the amount of both mucus and antibodies when catching a cold?

1. A A
2. B B
3. C C
4. D D

Which of the following chemical substances, when it increases, decreases the activity of plasma (B) cells?

1. A Lymphokines
2. B Perforin
3. C Interferons
4. D Complement proteins

From the figure in front of you:
Which of the choices in the following table represents (X), (Y), (Z) and (L)?

1. A X: antibody / Y: T cell / Z: antigen / L: plasma (B) cell
2. B X: helper T cell / Y: B cell / Z: antibody / L: memory (B) cell
3. C X: helper T cell / Y: killer T cell / Z: antibody / L: B cell
4. D X: bacterium / Y: B cell / Z: antibody / L: T cell

From the figure in front of you:
Which of the following represents the letter (M) and the letter (K), respectively?

1. A Interleukins / plasma (B) cell
2. B Cytokines / B cell
3. C Complement proteins / plasma (B) cell
4. D Lymphokines / B cell

Which of the following immune cells has the shortest life and works in cases of acute inflammation?

1. A A
2. B B
3. C C
4. D D

«Hypoplasia» is a disease caused by a genetic disorder that leads to atrophy of the thymus gland. What are the most important symptoms that appear on the patient?

1. A A decrease in the number of plasma B cells
2. B A decrease in the number of B cells
3. C A decrease in the number of lymphoid stem cells
4. D A decrease in innate immunity

What response may lead to the human body rejecting a transplanted organ?

1. A Secretion of chemokines
2. B Humoral immunity
3. C Cell-mediated immunity
4. D Secretion of interferons

The breakdown of red blood cells in a person with malaria releases some toxic substances in the body, and they are dealt with immunologically by ..........

1. A the inflammatory response
2. B the humoral response
3. C the cell-mediated response
4. D suppressor T cells

Which of the following cells must have its activity stopped for a liver transplant to succeed?

1. A TC
2. B TS
3. C Macrophages
4. D Mast cells

The following figures show the stages of the work of the macrophage in destroying the pathogen. Which of the following represents the correct order of events?

1. A (4) → (2) → (1) → (3)
2. B (2) → (4) → (1) → (3)
3. C (1) → (2) → (3) → (4)
4. D (4) → (3) → (2) → (1)

Which of the following substances has no role in the work of the third line of defense?

1. A Histamine
2. B Interleukins
3. C Complement proteins
4. D Perforin

Which of the following represents the correct immune response of the body when a pathogen enters it?

1. A Killer T cells make holes in infected cells and produce antibodies
2. B Killer T cells secrete cytokines and infected cells produce interferons
3. C Memory T cells produce antibodies and helper T cells secrete cytokines
4. D Helper T cells secrete cytokines and plasma cells produce antibodies

Which of the following represents a similarity between cytotoxic T cells and suppressor T cells?

1. A Recognizing the microbe
2. B The ability to produce lymphokines
3. C The ability to suppress the immune response
4. D The presence of an immune receptor on the cell surface

A person was infected by a virus for the first time. Which of the curves in the opposite graph represent the antigens and the antibodies, respectively?

1. A X / Y
2. B Y / X
3. C Y / Z
4. D Z / Y

Which of the following plays a role in attracting macrophages to the site of infection?

1. A Chemokines and cytokines
2. B Interleukins and interferons
3. C Cytokines and interleukins
4. D Chemokines and interferons

The opposite diagram shows the relationship between different types of lymphocytes, where the numbers from (8) to (11) represent secreted substances. Which of the choices in the following table can represent these cells?

1. A B: (6) / natural killer: (7) / cytotoxic T: (5) / phagocyte: (1)
2. B B: (5) / natural killer: (7) / cytotoxic T: (1) / phagocyte: (6)
3. C B: (1) / natural killer: (7) / cytotoxic T: (6) / phagocyte: (5)
4. D B: (5) / natural killer: (6) / cytotoxic T: (7) / phagocyte: (1)

Using the data in the opposite table, answer:
What does cell (2) represent?

1. A Helper T
2. B B
3. C Killer T
4. D Memory B

Using the data in the opposite table, answer:
What does cell (4) represent?

1. A Plasma B
2. B Memory B
3. C Helper T
4. D Phagocyte

Using the data in the opposite table, answer:
What does cell (6) represent?

1. A Helper T
2. B Plasma B
3. C B
4. D Macrophage

Which of the following cells does TS not affect?

1. A Mast cells
2. B Plasma B cells
3. C Helper T cells
4. D Cytotoxic T cells

Which of the following does not affect the permeability of cell membranes?

1. A Insulin
2. B Acetylcholine
3. C Histamine
4. D Lymphotoxins

Which of the following is not related to cell-mediated immunity?

1. A MHC protein
2. B TC
3. C TH
4. D Histamine

What chemical substance has its formation directly affected by the activity of helper T cells (TH)?

1. A Interleukins
2. B Histamine
3. C Complement proteins
4. D Chemokines

Which of the following cells has no shared role in humoral immunity and cell-mediated immunity?

1. A Macrophages
2. B Helper T cells
3. C Cytotoxic T cells
4. D Suppressor T cells

The following graph shows the concentration of the three types of T cells in the blood of a person after a pathogen entered. Which of the following choices can represent these cells?

1. A X: TC / Y: TH / Z: TS
2. B X: TS / Y: TC / Z: TH
3. C X: TH / Y: TC / Z: TS
4. D X: TC / Y: TS / Z: TH

What process directly precedes displaying the antigen on the surface of the macrophage?

1. A The macrophage swallowing the pathogen
2. B Breaking down the pathogen into antigens
3. C Binding of the MHC protein with the antigen
4. D TH cells recognizing the antigen

Which of the following is correct about cytotoxic T lymphocytes?

1. A Mature cells that are active in cell-mediated immunity
2. B Mature cells that are active in humoral immunity
3. C Immature cells that are active in cell-mediated immunity
4. D Immature cells that are active in humoral immunity

The opposite figure shows the structure of a virus. Through which structure can B cells recognize this virus?

1. A (X) only
2. B (Y) only
3. C (X), (Y)
4. D (X), (Z)

The opposite drawing shows one of the mechanisms of the immune system in humans, and (M) represents a body cell. What are the types of the two cells (X), (L) and the two substances (Y), (Z), respectively?

1. A Infected cell, TC cell / interferons, perforin
2. B TH cell, TC cell / cytokines, perforin
3. C Infected cell, TC cell / perforin, interferons
4. D TC cell, infected cell / interleukins, perforin

Which of the following statements is correct for natural killer (NK) cells?

1. A They are not specific to a certain type of antigen
2. B They do not contain lytic enzymes
3. C They are a type of T cell
4. D They belong to the third line of defense only

The figure in front of you shows the mechanism of work of one of the immune cells:
Which of the following choices expresses (X), (Y) and (Z)?

1. A X: natural killer cell / Y: phagocyte / Z: perforin
2. B X: cytotoxic T cell / Y: virus-infected cell / Z: perforin
3. C X: B cell / Y: transplanted tissue / Z: lymphotoxins
4. D X: killer T cell / Y: cancer cell / Z: lymphotoxins

The figure in front of you shows the mechanism of work of one of the immune cells:
What chemical substances does cell (Y) produce?

1. A Interleukins
2. B Histamine
3. C Interferons
4. D Lymphokines

Which of the following statements is not correct about (TH) cells?

1. A They control the work of (B) and (TC) lymphocytes
2. B They do not control the work of all white blood cells
3. C They secrete interleukins when they bind to (B) cells
4. D They can recognize the antigen without the need for the MHC protein

A child suffers from a genetic disease that caused atrophy of part of the thymus gland. What is the result of this?

1. A Weak humoral immunity only
2. B Weak cell-mediated immunity only
3. C Weak acquired immunity
4. D Disappearance of the MHC protein from immune cells

The figure shows a pathogen. Which of the following can bind directly to structure (X)?

1. A Receptors of B cells and helper T cells
2. B Receptors of B cells and complement proteins
3. C Receptors of helper T cells and the antibody
4. D Receptors of B cells and the antibody

The opposite graph shows the concentration of antibodies formed after vaccinating two children (X) and (Y) against yellow fever. Which of the following choices cannot be a possible explanation?

1. A Child (X): lives in an area where the disease is endemic / Child (Y): lives in an area free of this disease
2. B Child (X): got the same vaccination before / Child (Y): gets the vaccination for the first time
3. C Child (X): vaccinated with the vaccine (weakened microbe) / Child (Y): vaccinated with the serum (ready-made antibodies)
4. D Child (X): secondary immune response / Child (Y): primary immune response

What is the function of memory (B) cells?

1. A Swallowing bacteria that attack the body again
2. B Producing antibodies
3. C Producing plasma B cells
4. D Killing virus-infected cells

Which of the following distinguishes adaptive immunity from natural immunity?

1. A The inflammatory response
2. B Memory cells
3. C Lysosomes
4. D Natural killer cells

Which of the following statements is correct about the immune response?

1. A It produces immunoglobulins
2. B It always leads to the destruction of pathogens
3. C It depends mainly on mast cells
4. D It takes place only through innate immunity

A person may catch influenza several times in one year because of the high rate of change in the genetic material of the influenza virus. What is the immune cause of the repeated infection?

1. A Primary immunity is not effective in destroying the virus
2. B Secondary immunity is not effective in destroying the virus
3. C Inhibition of memory cells
4. D Inhibition of (B) cells

Which of the following statements does not apply to lymphocytes?

1. A Each memory B lymphocyte can produce different types of antibodies
2. B Some B and T lymphocytes differentiate into memory cells
3. C Plasma B cells produce antibodies that circulate in the blood
4. D Some T lymphocytes secrete substances that attract phagocytes to the site of infection

The opposite graph shows the concentration of antibodies in the blood plasma of a person exposed to a pathogen for the first time:
Why are there no antibodies in the first three days?

1. A The immune cells cannot recognize the antigens of the pathogen
2. B The phagocytes cannot engulf the pathogen
3. C Plasma B cells have not been formed
4. D The strength of the pathogen at the moment it enters the body

The opposite graph shows the concentration of antibodies in the blood plasma of a person exposed to a pathogen for the first time:
If the same pathogen attacked this person on the fifteenth day, what do you expect the antibody concentration to be on the seventeenth day?

1. A Zero
2. B 10
3. C 20
4. D More than 20

The opposite graph shows the immune response in humans. Which of the choices in the following table is correct about (X), (Y) and (Z)?

1. A X: antibodies / Y: may result from vaccination / Z: fast response
2. B X: lymphokines / Y: results from the response of memory (B) cells / Z: fast response
3. C X: antibodies / Y: fast response / Z: results from the response of (T) cells
4. D X: histamine / Y: results from the first infection / Z: produces memory cells

Which of the following graphs represents the stages of acquired immunity of a person exposed to the same pathogen again?

1. A A
2. B B
3. C C
4. D D

The opposite graph shows the concentration of some antibodies in the blood of a person. In which of the following cases are memory cells responsible for the immune response?

1. A (X), (Z)
2. B (Y), (Z)
3. C (Z) only
4. D (Y) only

The presence of 50 types of memory (B) cells confirms that .......... entered the blood.

1. A 50 types of antigens
2. B 50 antigens of the same type
3. C the same vaccine 50 times
4. D 50 different foreign bodies

Which of the following is correct if a change in the structure of the gene responsible for forming the protein coat of the (COVID-19) virus led to the formation of a protein similar in its chemical structure to the protein coat of a virus that was vaccinated against before?

1. A Helper T cells cannot recognize it
2. B It is recognized by memory cells and antibodies are produced against it
3. C B cells cannot recognize it
4. D It is recognized by phagocytes without being destroyed

In a family, the older brother was infected by a microbe and recovered from it very slowly, so the parents decided to inject the younger brother with a vaccine for this microbe. Which of the following lymphocytes will produce antibodies against the antigens of this weakened microbe in the younger brother's blood?

1. A Plasma B cells
2. B B cells
3. C Memory B cells
4. D Memory T cells

The opposite graph shows the amount of some antibodies in the blood of a person in January (A) and March (B). Which of the following statements applies to the two antigens (X) and (Y)?

1. A The two antigens are different and each attacks the body for the first time
2. B The two antigens belong to the same microbe attacking the body for the first time
3. C The two antigens belong to the same microbe attacking the body for the second time
4. D The two antigens are different; (X) attacks the body for the second time, while (Y) attacks the body for the first time

The opposite figure represents the immune response of the human body when a pathogen enters. Study it, then answer:
What do the cells marked with the letter (Z) represent?

1. A Helper T
2. B Memory T
3. C Plasma B
4. D Memory B

The opposite figure represents the immune response of the human body when a pathogen enters. Study it, then answer:
Why does the number of antibodies increase in stage (B) more than in stage (A)?

1. A Because the number of antigens in (B) is greater than in (A)
2. B Because the number of B cells increases in stage (B)
3. C Because the types of antigens in (B) are more than in (A)
4. D Because the same microbe enters the body for the second time in stage (B)

The opposite figure represents the immune response of the human body when a pathogen enters. Study it, then answer:
After the microbe is destroyed, which of the following do suppressor T cells inhibit?

1. A (X) only
2. B (Y) only
3. C (X), (Y)
4. D (Y), (Z)

The following diagram shows some stages of acquired immunity inside the body. What do the immune response (X) and the substance (Y) represent, respectively?

1. A Primary / cytokines
2. B Primary / perforin
3. C Secondary / cytokines
4. D Secondary / perforin

During the primary immune response, the following happens:
(1) B lymphocytes differentiate and form plasma B cells.
(2) B lymphocytes divide by mitosis.
(3) Specific antibodies are produced.
(4) Activated helper T cells secrete interleukins.
(5) Helper T cells recognize the antigen bound to the MHC protein.
Which of the following choices represents the correct order of the previous steps?

1. A (2) → (1) → (4) → (3) → (5)
2. B (2) → (4) → (3) → (1) → (5)
3. C (5) → (4) → (2) → (1) → (3)
4. D (5) → (4) → (3) → (2) → (1)

The opposite graph shows the concentration of antibodies in the blood of three persons (A), (B) and (C) who were infected by the same type of bacteria. Which of the three persons was given the serum (ready-made antibodies) for this type of bacteria?

1. A (A) only
2. B (B) only
3. C (A), (C)
4. D (B), (C)

Which of the following can be a cause of the slowness of the primary immune response?

1. A Spread of the microbe in the body tissues
2. B Delay in activating (B) cells
3. C Absence of helper T cells
4. D Absence of plasma B cells

From the opposite table, which shows the antibody concentration in the blood of a person during 50 days, from 1 March to 19 April, for the same pathogen:
When was the first exposure to infection?

1. A 2 March
2. B 8 March
3. C 10 March
4. D 16 March

From the opposite table, which shows the antibody concentration in the blood of a person during 50 days, from 1 March to 19 April, for the same pathogen:
When was the second exposure to infection?

1. A 16 March
2. B 2 April
3. C 5 April
4. D 14 April

The opposite graph shows the immune response on the first infection and the second infection by a certain microbe:
In which periods does the work of memory B cells appear?

1. A A → B
2. B B → C
3. C D → E
4. D E → F

The opposite graph shows the immune response on the first infection and the second infection by a certain microbe:
During which periods does the activity of lymphokine proteins increase?

1. A A → B , D → E
2. B B → C , E → F
3. C A → B , E → F
4. D B → C , D → E

The opposite graph shows the concentration of antibodies produced as a response to a type of antigen:
On which of the following days is the formation of memory cells expected to start?

1. A The fifth day
2. B The tenth day
3. C The twentieth day
4. D The twenty-second day

The opposite graph shows the concentration of antibodies produced as a response to a type of antigen:
On which of the following days are plasma B cells expected to be produced?

1. A The fifth day and the fifteenth day
2. B The fifth day and the twentieth day
3. C The fifth day and the thirtieth day
4. D The fifteenth day and the thirtieth day

The opposite graph shows the concentration of antibodies produced as a response to a type of antigen:
In the secondary immune response, on which of the following days is the secretion of lymphokine proteins expected to start?

1. A The fifteenth day
2. B The twentieth day
3. C The twenty-fifth day
4. D The twenty-ninth day

Knowing that the serum is ready-made antibodies against the pathogenic microbe, while the vaccine is the pathogenic microbe in a dead or weakened form:
Which of the following can be concluded?

1. A The serum gives temporary protection, while the vaccine gives protection for long periods
2. B The serum gives protection for long periods, while the vaccine gives temporary protection
3. C Both the serum and the vaccine give protection for long periods
4. D Both the serum and the vaccine give temporary protection

Knowing that the serum is ready-made antibodies against the pathogenic microbe, while the vaccine is the pathogenic microbe in a dead or weakened form:
In the first attempts to limit the spread of coronavirus infection, an amount of blood was taken from the patient right after recovery. How is this explained?

1. A Isolating the virus and identifying its structure
2. B Separating the virus antigens and using them as a vaccine
3. C Separating the antibodies and using them as a serum
4. D Separating the active lymphocytes

Knowing that the serum is ready-made antibodies against the pathogenic microbe, while the vaccine is the pathogenic microbe in a dead or weakened form:
Which of the following can be concluded from the opposite graph?

1. A The pathogen stimulates the immune cells more strongly than the vaccine
2. B The vaccine used is active and works efficiently
3. C The vaccine used was not prepared properly
4. D The vaccine inhibits the activity of (B) cells

A person had measles, and several years later he got a tumor in the thymus gland, which led to removing this gland. What happens if this person is exposed to the same microbe that causes measles again, one year after the removal?

1. A He will be infected again because the lymphoid stem cells do not mature
2. B He will be infected again because T lymphocytes do not differentiate
3. C He will not be infected again because memory cells were formed during the first exposure
4. D He will not be infected again because antibodies were formed during the first exposure

The opposite graph shows the antibody response when a person is injected with antigen (X) first, then with the two antigens (X) and (Y) after a period. Which of the opposite curves represents the primary response to antigen (Y)?

1. A A
2. B B
3. C C
4. D D

In the opposite graph, what do cells (X), (Y) and (Z) represent?

1. A X: macrophage / Y: B / Z: plasma B
2. B X: T / Y: B / Z: killer T
3. C X: B / Y: plasma B / Z: memory B
4. D X: B / Y: memory B / Z: plasma B

The opposite graph shows the degree of the immune response in the body of a person vaccinated with a vaccine. What is the cause of the symptoms appearing in stage (X)?

1. A The vaccine used is for another pathogen
2. B The vaccine used was not prepared properly
3. C The immune cells did not respond to the vaccine
4. D The vaccine inhibits the activity of (B) cells

What lines and means of defense does the influenza virus meet until it reaches the lung cells?

Study the opposite figure, which shows the role of one type of white blood cells in fighting infection:
(1) What is cell (X)?
(2) Is cell (X) specific or non-specific? Explain your answer.
(3) How is microbe (Y) destroyed?
(4) What is the correct order of the four stages?

Study the opposite figure, which shows the inflammatory response, then deduce:
(1) What are cell (Y) and cell (Z)?
(2) What is substance (X)?
(3) What happens if this line of defense fails to destroy the bacteria?

The opposite figure shows the stages of a white blood cell swallowing pathogenic bacteria:
(1) What is the correct order of the stages in front of you according to when they happen?
(2) What is organelle number (1)? What is its importance?
(3) Name three types of cells that carry out the same process shown in the figure.

Study the opposite diagram, then answer:
(1) What substances does cell (Y) produce?
(2) Where does cell (X) mature?

The opposite figure shows the work of some cells of the immune system. Answer:
(1) What substance is secreted in case (X)?
(2) What type of immune cell is in case (Z)? What substance does it secrete?
(3) Where are the immune cells in case (Y) formed and activated?

The following table shows the result of a blood test of a person after a pathogen attacked his body:
TH: result 25 (normal level from 20 to 30).
TC: result 30 (normal level from 30 to 40).
B: result 7 (normal level from 5 to 10).
NK: result 2 (normal level from 1 to 3).
What type of immunity is active in this person? Explain your answer.

The opposite graph shows the relationship between the number of plasma B cells and the concentration of interleukins in the blood:
(1) What is the cause of the increase in the concentration of interleukins in the blood?
(2) Which cells decrease in number as the number of plasma B cells increases? Explain your answer.
(3) What proteins accompany the increase of plasma B cells? What is their importance?

The opposite graph shows the concentration of antigens and the concentration of antibodies in the blood of a person infected by a virus for the first time:
(1) Which of the two curves represents the antigens, and which represents the antibodies? What is your scientific explanation for that?
(2) Which cells are responsible for the decrease in antibody production? When are they activated?

The following table shows the extent of the immune response of three organisms of different classification (numbers in thousands of antibodies):
Organism (1): before the first infection zero, during the infection zero, after the infection zero.
Organism (2): before the first infection zero, during the infection 50, after the infection 20
Organism (3): before the first infection zero, during the infection 70, after the infection 64
What can be concluded about these organisms?

The two opposite graphs show the amount of bacteria and the concentration of antibodies in the blood of two persons infected by the same type of bacteria. Answer the following:
(1) Which of the two persons was infected by this type of bacteria before?
(2) Name the type of lymphocytes responsible for the immune response of the first person.
(3) Which of the two persons shows the symptoms of the disease?

The opposite graph shows a study done by two researchers on the immune state of two persons exposed to malaria. Study it, then answer:
(1) In the light of your study, explain how we can recognize malaria infection.
(2) Which of the two persons shows the symptoms of malaria first? Explain your answer.
(3) How does this parasite reproduce inside the human body?

In the middle of last November, scientists succeeded in isolating an antibody from a patient with AIDS, called (N6), which succeeded in resisting 98% of the strains of the AIDS virus in laboratory tests. Scientists hope to inject patients with it to use it for temporary protection from the virus. What is the type of immunity after the injection?

Elderly people catch influenza because of their weak immunity, so they are injected with a vaccine (the microbe in a dead or weakened form) to increase their immunity. What is the explanation for that?

Which of the following takes place during the inflammatory response? (Trial exam / June 2021)

1. A Secretion of substances that reduce the blood supply in the infected area
2. B Increase in the activity of phagocytes
3. C Increase in the production of white blood cells in the bone marrow
4. D Secretion of interferons from mast cells

When a person eats food contaminated with Salmonella bacteria, which defensive means respond, in order? (1st session 2021)

1. A Mucus / stomach secretions
2. B Saliva / Peyer's patches
3. C Saliva / stomach secretions
4. D Peyer's patches / mucus

During the direct penetration of a microbe, the wall of a plant cell swelled. What immune means in humans is similar to this change? (1st session 2022)

1. A The skin
2. B Tears
3. C Inflammation
4. D Earwax

Study the following table, which shows the percentages of some white blood cells in a blood test of a person, then deduce: what chemical substance increases in the body of this person? (2nd session 2022)
Neutrophils: result 70 (normal range from 40 to 60).
Monocytes: result 10 (normal range from 2 to 8).
Lymphocytes: result 25 (normal range from 20 to 30).

1. A Perforin
2. B Lymphokines
3. C Complement proteins
4. D Histamine

Which of the following is not one of the functions of the antibody? (2nd session 2022)

1. A Activating the inflammatory response
2. B Converting soluble antigens into insoluble ones
3. C Preventing toxins from binding to cells
4. D Preventing virus coats from sticking to cell membranes

Study the opposite figure, then deduce: which letter points to the cell / organ targeted by the secretions of cell (B)? (2nd session 2023)

1. A A
2. B F
3. C E
4. D D

Which immune cells can cause inflammation and engulf bacteria at the site of infection? (1st session 2023)

1. A Neutrophils
2. B Monocytes
3. C Macrophages
4. D Basophils

Which of the following immune means is a physical barrier and not a chemical one? (1st session 2024)

1. A Mucus and saliva
2. B The horny layer and cilia
3. C Tears and sweat
4. D HCl and earwax

What is the cause of the redness, pain and swelling of tissues at the site of inflammation? (2nd session 2024)

1. A Accumulation of the fluid leaking from the blood
2. B Accumulation of interferons at the site of inflammation
3. C Phagocytes swallowing the microbe
4. D Tissue damage from a cut wound

Which of the following is correct about the cell and its function? (Sample exam 2025)

1. A Eosinophils - produce antibodies
2. B B lymphocytes - attack foreign cells directly
3. C Basophils - secrete histamine
4. D T lymphocytes - engulf bacteria

Which cells are directly affected by histamine? (Sample exam 2025)

1. A Basophils
2. B Macrophages
3. C Mast cells
4. D Body cells

What process does cell (A) show? (Sample exam 2025)

1. A Release of histamine
2. B Phagocytosis
3. C Swelling of tissues
4. D Passage of interferons

Study the following table, which shows the result of a blood test of a person, then determine: what type of immunity is active in this person? (Trial exam / June 2021)
TH: result 50 (normal level from 20 to 30).
TC: result 30 (normal level from 30 to 40).
B: result 20 (normal level from 5 to 10).
NK: result 2 (normal level from 1 to 3).

1. A Humoral
2. B Cell-mediated
3. C Non-specific
4. D Inherited

What substance's secretion is evidence of the integration between humoral and cell-mediated immunity together? (Trial exam / June 2021)

1. A Cytokines
2. B Lymphokines
3. C Interferons
4. D Histamine

From the opposite figure, which of the following is found at immunity level (C) only? (1st session 2021)

1. A Interferons
2. B Antibodies
3. C Histamine
4. D Lymphokines

The opposite figure shows one of the stages of acquired immunity. What is substance (A)? (1st session 2021)

1. A Cytokines
2. B Perforin
3. C Lymphokines
4. D Lymphotoxins

A person was infected by a microbe, and medical tests showed a rise in the level of antibodies and activating proteins such as cytokines. Which immune cells have a shared role in increasing both cytokines and antibodies? (2nd session 2021)

1. A B cells
2. B Killer T cells
3. C Natural killer cells
4. D Phagocytes

Study the following diagram, which shows the relationship between some cells of the immune system in humans:
What are the names of cells (X), (Y) and (Z), respectively? (2nd session 2021)

1. A B / plasma B / memory B
2. B B / memory B / plasma B
3. C Plasma B / B / memory B
4. D Plasma B / memory B / B

Which of the following is not affected when there is a defect in the gene that forms the hormone thymosin? (1st session 2022)

1. A Perforin
2. B Antibodies
3. C Interferons
4. D Lymphokines

Which of the following indicates an increase in the immune response of a person who had a kidney transplant? (1st session 2022)

1. A Cytokines
2. B Interleukins
3. C Interferons
4. D Perforin

Study the drawing in front of you, then determine:
What are the two substances (X) and (Y), respectively? (1st session 2022)

1. A Interleukins / perforin
2. B Cytokines / lymphokines
3. C Interleukins / cytokines
4. D Perforin / lymphotoxins

What is the result of a gene mutation that led to a decrease in the number of cells of structure (X) in a child? (2nd session 2022)

1. A A decrease in the production of lymphoid stem cells
2. B An increase in the differentiation of T cells into their different types
3. C A severe deficiency in acquired immunity
4. D An increase in the number of plasma B cells

Study the opposite figure, which shows the role of two types of lymphocytes. What substances were produced in (1) and (2), respectively? (Trial exam 2023, Sample exam 2025)

1. A Complement proteins / interleukins
2. B Lymphotoxins / lymphokines
3. C Interleukins / complement proteins
4. D Perforin / cytokines

Which of the following substances plays no role in healing liver cells from virus (C)? (Trial exam 2023)

1. A Interferons
2. B Histamine
3. C Lymphotoxins
4. D Antibodies

A blood test of a person showed a type of bacteria in the blood sample. Which immune cells are responsible for protecting this person? (Trial exam 2023, Sample exam 2025)

1. A Natural killer cells
2. B Plasma B cells
3. C Memory T cells
4. D Cytotoxic T cells

Which of the following substances is not a component of the third line of defense in the human body? (Trial exam 2023)

1. A Cytokines
2. B Interleukins
3. C Interferons
4. D Lymphokines

What substance do natural killer cells secrete? (1st session 2023)

1. A Perforin
2. B Histamine
3. C Lymphokines
4. D Cytokines

What is the correct order of the work of humoral immunity and cell-mediated immunity? (1st session 2023, Sample exam 2025)

1. A Simultaneous
2. B Successive
3. C Separate
4. D One stops the other

What distinguishes B cells from plasma B cells? (1st session 2023)

1. A Their ability to produce antibodies
2. B The line of defense they take part in
3. C The presence of receptors on their surface
4. D Their ability to secrete cytokines

Study the opposite schematic figure of one of the immune mechanisms in humans, then deduce: what are the cells marked with the letters (X) and (Y), respectively? (2nd session 2023)

1. A Activated helper T / natural killer
2. B Activated helper T / cytotoxic T
3. C Activated helper T / suppressor T
4. D Activated helper T / B

What substance acts as a mediator between immune cells and body cells? (2nd session 2023)

1. A Interferons
2. B Cytokines
3. C Lymphokines
4. D Lymphotoxins

Why are both B cells and helper T cells specific cells? (2nd session 2023)

1. A Because both belong to cell-mediated immunity
2. B Because both belong to humoral immunity
3. C Because they can recognize more than one type of virus
4. D Because of the presence of one type of receptor on their membranes

What immune response in humans is equivalent to hypersensitivity in plants? (2nd session 2023)

1. A Saliva and tears
2. B The inflammatory response
3. C Humoral immunity
4. D Cell-mediated immunity

Suppose a new disease that inhibits the immune system was discovered. Which of the following indicates that the disease affects B cells specifically and not helper T cells or cytotoxic T cells? (Sample exam 2025)

1. A A decrease in the production of interleukin
2. B A decrease in the production of interferon
3. C A decrease in the number of plasma cells
4. D A decrease in the production of chemokines

Which of the following is not a shared feature between macrophages and B lymphocytes? (Sample exam 2025)

1. A Both present the antigen to helper T cells
2. B Both contain the MHC protein in their cytoplasm
3. C Both break down the pathogen into antigens
4. D Both contain receptors specific to one type of antigen

Which lymphocytes are similar in their mechanism of destroying the pathogen? (Sample exam 2025)

1. A Natural killer and cytotoxic T
2. B Phagocytes and helper T
3. C B and phagocytes
4. D Natural killer and B

Which cells do Ts cells bind to after the microbe is removed? (Sample exam 2025)

1. A Plasma B, cancer cells
2. B Helper T, B, natural killer
3. C Macrophages, cytotoxic T
4. D Helper T, plasma B, cytotoxic T

How many types of receptors are found in the membranes of each of the B cells and the helper T cells that attack the measles virus when it attacks the human body? (Sample exam 2025)

1. A One type
2. B Two different types
3. C One type and an MHC protein
4. D Two types and two MHC proteins

What is the shared feature between lymphotoxins and interferons? (1st session 2025)

1. A Both destroy virus-infected body cells
2. B Both prevent the virus from entering body cells
3. C Both are secreted by immune cells
4. D Both activate certain genes in body cells

What types of immune cells contain the MHC protein? (2nd session 2025)

1. A B cells and macrophages
2. B Macrophages only
3. C B cells only
4. D B cells and plasma B cells

In which of the following lines of defense are the cells activated by interleukins? (2nd session 2025)

1. A The second line of defense
2. B The third line of defense
3. C The second and third lines of defense
4. D All lines of defense

Each of the following substances acts as a means of communication between different types of immune cells except .......... (2nd session 2025)

1. A cytokines
2. B lymphokines
3. C lymphotoxins
4. D interleukins

Which of the following lymphoid organs plays a main role in the maturation of acquired immunity cells? (Sample exam 2026)

1. A The tonsils
2. B Peyer's patches
3. C The thymus gland
4. D The spleen

What is the first type of white blood cells to attack pathogens when they invade the body? (Sample exam 2026)

1. A Macrophages only
2. B B lymphocytes only
3. C Macrophages and B lymphocytes
4. D Macrophages and helper T cells

The complex formed by the binding of the antigen with the MHC protein is formed .......... (Sample exam 2026)

1. A on the membrane of the macrophage only
2. B inside the cytoplasm of B cells only
3. C on the membrane of the macrophage and the membrane of B cells
4. D in the cytoplasm of B cells and the cytoplasm of the macrophage

The opposite figure shows some steps of humoral immunity. Which of the following is correct for (X), (Y) and (Z)? (Sample exam 2026)

1. A They have the same chemical structure
2. B They are specific to different antigens
3. C They are produced at the same time
4. D They have different antigen-binding sites

Which of the following immune systems in humans will be activated when bacteria enter with inhaled air? (Sample exam 2026)

1. A Innate immunity
2. B Acquired immunity
3. C Acquired immunity after innate immunity succeeds
4. D Innate and acquired at the same time

In the opposite figure, cell number (1) may be .......... (Sample exam 2026)

1. A a mature B cell
2. B a helper T cell
3. C a plasma B cell
4. D a macrophage

Usually, vitamin B12 enters the stomach and binds to a factor produced by cells in the stomach wall, then the complex (vitamin + factor) moves to the small intestine to be absorbed into the blood. In pernicious anemia, plasma cells produce antibodies against this factor, so the vitamin is not absorbed. Which of the following expresses the pathway followed in the case of this disease? (Sample exam 2026)

1. A A
2. B B
3. C C
4. D D

What distinguishes natural killer cells from cytotoxic T cells? (1st session 2024)

1. A Their immune response belongs to the third line of defense only
2. B Their immune response is slower when attacking infected cells
3. C Their immune response is specific to a certain microbe
4. D Their immune response is faster when attacking infected cells

The cells of which of the following lines of defense activate the other? (1st session 2024)

1. A The cells of each of the second and third lines of defense activate the other
2. B The cells of the second line of defense activate the cells of the third line of defense only
3. C The cells of the third line of defense activate the cells of the second line of defense only
4. D There is no mutual activation relationship between the cells of the second and third lines of defense

Which cells play immune roles in both the second and third lines of defense? (2nd session 2024)

1. A Macrophages and natural killer cells
2. B B and T cells
3. C Basophils and mast cells
4. D Phagocytes and B cells

What feature distinguishes B cells from macrophages? (2nd session 2024)

1. A They contain the MHC protein
2. B They recognize the pathogen
3. C They can display the antigen on their surface
4. D They bind to TH cells through their receptors

Which cells are not affected by lymphokines? (1st session 2025)

1. A Plasma B
2. B Helper T
3. C Memory B
4. D Cytotoxic T

The opposite graph expresses the rate of the immune response of a person infected by the measles virus. Which cells increase in number in the period from (A) to (B)? (2nd session 2021)

1. A Suppressor T
2. B Memory B
3. C Cytotoxic T
4. D Macrophages

When a person is infected by the same type of bacteria twice, what is the difference between the antibodies in the first infection and the antibodies in the second infection? (1st session 2022)

1. A The type of antibodies
2. B The structure of the variable region
3. C The amount of antibodies
4. D The structure of the constant region

A person was infected by a type of bacteria, then was infected again by bacteria of another strain. Which of the following is responsible for the immune response to resist these bacteria when they reach the blood? (1st session 2022)

1. A Monocytes
2. B Antibodies produced by memory (B) cells
3. C Antibodies produced by plasma cells
4. D Eosinophil white blood cells

What distinguishes the mechanism of work of memory B cells from B cells against the same microbe? (2nd session 2024)

1. A They do not need to divide and differentiate into plasma cells
2. B They do not need activation by TH cells
3. C They do not need to recognize the antigen again
4. D There is no difference between their mechanisms of work

A person was infected by microbe (A) at the age of 5 and recovered, then was infected by microbe (B) at the age of 7 and recovered, then was infected by microbe (A) at the age of 30 and showed no symptoms of the disease. How many times did the immune system of this person give primary and secondary immunity, respectively? (Sample exam 2025)

1. A Primary 2, secondary 1
2. B Primary 1, secondary 1
3. C Primary 1, secondary 2
4. D Primary 2, secondary 2

The following table shows three immune mechanisms: (Sample exam 2025)
Mechanism (A): monocytes, phagocytes, basophils, mast cells.
Mechanism (B): helper T, B, natural killer, killer T.
Mechanism (C): memory T, memory B, phagocytes, killer T.
Which letter / letters point to the mechanism that is not accompanied by the appearance of disease symptoms?

1. A (A) and (B)
2. B (A) and (C)
3. C (A) only
4. D (C) only

Which of the following cells can recognize the type of antigen directly? (Sample exam 2026)
(1) Plasma B. (2) Helper T. (3) Macrophage. (4) B. (5) Memory B.

1. A (1) and (3)
2. B (2) and (4)
3. C (4) and (5)
4. D (3) and (5)