Question

1. the diagram below represents an event that occurs in the blood. which statement describes this event?

(1) cell a is a white blood cell releasing antigens to destroy bacteria.
(2) cell a is a cancer cell produced by the immune system and it is helping to prevent disease.
(3) cell a is a white blood cell engulfing disease - causing organisms.
(4) cell a is protecting bacteria so they can reproduce without being destroyed by the predators.

Explanation:

• White blood cells (phagocytes) are known for engulfing (phagocytosing) disease - causing organisms (pathogens) like bacteria.
• Option (1) is incorrect because white blood cells release antibodies (not antigens) to fight bacteria. Antigens are on the surface of pathogens.
• Option (2) is wrong as cancer cells are not produced by the immune system to prevent disease. The immune system usually attacks cancer cells.
• Option (4) is incorrect as white blood cells do not protect bacteria. Their role is to destroy pathogens.

Answer:

(3) Cell A is a white blood cell engulfing disease - causing organisms.