Answer: mast cells.
- A mast cells
- B red blood cells
- C platelets
- D osteocytes
Correct answer: A. mast cells
Explanation: Allergens bind IgE on mast cells, causing them to release histamine and serotonin. These cause sneezing, watery eyes and other allergy symptoms; anti-histamines counter this.
The Plasmodium parasite needs both hosts: the female Anopheles mosquito injects sporozoites while biting (infecting the human liver and RBCs, causing the malaria fever cycle), then picks up gametocytes from an infected person's blood, completing the parasite's sexual stage inside the mosquito.
Concept context
Pathogens, infectious diseases, non-infectious diseases, drugs, cancer, and public health. High NEET importance.