Question

what are antibodies?
○ proteins that recognize and stick to the antigens
○ special white blood cells in the lymph
○ the harmful part of pathogen cells
○ medicines that kill bacteria in the body

Explanation:

To determine the correct answer, we analyze each option:

• Option 1: Antibodies are proteins (immunoglobulins) produced by B - cells. Their main function is to recognize specific antigens (foreign substances) and bind to them, marking them for destruction or neutralizing them. This matches the definition of antibodies.
• Option 2: Special white blood cells in the lymph are likely referring to lymphocytes (like B and T cells), not antibodies. Antibodies are proteins, not cells.
• Option 3: The harmful part of pathogen cells is the antigen, not the antibody. Antibodies act against antigens.
• Option 4: Medicines that kill bacteria are antibiotics, not antibodies. Antibodies are part of the immune system, not external medicines.

Answer:

A. proteins that recognize and stick to the antigens