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Question 1:

What is immunity?

A) The ability of an organism to fight off infections
B) The presence of antibodies in the blood
C) The body's response to injury
D) The ability of an organism to reproduce

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Explanation: The correct answer is A) The ability of an organism to fight off infections. Immunity refers to the body's ability to defend itself against harmful pathogens, such as bacteria, viruses, and parasites, and prevent or limit infection.

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Question 2:

Which type of immunity is present at birth and provides immediate, nonspecific protection against a wide range of pathogens?

A) Innate immunity
B) Adaptive immunity
C) Active immunity
D) Passive immunity

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Explanation: The correct answer is A) Innate immunity. Innate immunity is the first line of defense against pathogens and is present at birth. It provides immediate, nonspecific protection through physical barriers, such as skin and mucous membranes, as well as cellular and chemical defenses.

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Question 3:

Which cells of the immune system are responsible for recognizing and eliminating specific pathogens?

A) Antibodies
B) T cells
C) B cells
D) Phagocytes

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Explanation: The correct answer is B) T cells. T cells are a type of white blood cell that plays a central role in adaptive immunity. They recognize and eliminate specific pathogens by directly attacking infected cells or by releasing chemical signals to activate other immune cells.

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Question 4:

What is the primary function of antibodies?

A) Phagocytosis of pathogens
B) Activation of T cells
C) Direct killing of infected cells
D) Recognition and neutralization of pathogens

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Explanation: The correct answer is D) Recognition and neutralization of pathogens. Antibodies, also known as immunoglobulins, are proteins produced by B cells in response to specific pathogens or antigens. They recognize and bind to pathogens, marking them for destruction or neutralizing their harmful effects.

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Question 5:

What is the purpose of vaccines?

A) To provide passive immunity against specific diseases
B) To stimulate the production of antibodies
C) To directly kill pathogens in the body
D) To suppress the immune response

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Explanation: The correct answer is B) To stimulate the production of antibodies. Vaccines are designed to stimulate the immune system to produce an immune response against specific pathogens without causing the actual disease. This leads to the production of antibodies and the development of immunity, providing protection against future infections.