Identify the correct sequence of stages in the life cycle of Plasmodi…

The correct answer is Option (2) → (D), (C), (B), (A)

(D) Sporozoites enter the human body — this comes first. Plasmodium enters a person as sporozoites, the infective form, through the bite of an infected female Anopheles mosquito.

(C) Parasites multiply in liver and then attack RBCs — this comes second. The parasites first multiply inside the liver cells. Then they attack the red blood cells and make them burst.

(B) Gametocytes develop in RBCs — this comes third. Some of the parasites inside the red blood cells change into gametocytes, the forms that can infect a mosquito.

(A) Sporozoites stored in the salivary gland of female Anopheles — this comes last. A mosquito that bites an infected person takes in the gametocytes. The parasites develop and multiply in the mosquito and form sporozoites, which are stored in its salivary glands. The next bite passes them to another person, and the cycle begins again.

NCERT Extract:
Common Diseases in Humans – “… Plasmodium enters the human body as sporozoites (infectious form) through the bite of infected female Anopheles mosquito. The parasites initially multiply within the liver cells and then attack the red blood cells (RBCs) resulting in their rupture. The rupture of RBCs is associated with release of a toxic substance, haemozoin, which is responsible for the chill and high fever recurring every three to four days. When a female Anopheles mosquito bites an infected person, these parasites enter the mosquito’s body and undergo further development. The parasites multiply within them to form sporozoites that are stored in their salivary glands. When these mosquitoes bite a human, the sporozoites are introduced into his/ her body, thereby initiating the events mentioned above.”