Question

Which of the following is the adult stage of Plasmodium?
A. Trophozoite
B. Cryptozoite
C. Phanerozoite
D. None of the above

Answer 1

Hint: The Plasmodium has a unique and complicated life cycle involving two hosts. During feeding on the blood of humans, a malaria-infected female Anopheles mosquito inoculates sporozoites into the human host.
Sporozoites infect liver cells and mature into schizonts, which rupture and release merozoites.

Complete answer: When an Anopheles mosquito bites a healthy individual Plasmodium is introduced into the human blood in the form of the infective stage known as the sporozoite.
The injected sporozoites invade the hepatocyte cells i.e. the liver cells in the liver and then a sporozoite actively feeds on its cytoplasm and grows into an outsized (about 45 in diameter) and spherical size called as Cryptozoic.
After invading an erythrocyte, it becomes a rounded, disc-like advanced structure called trophozoites.
It is this adult stage of the parasite which is responsible for the production of the gametocytes.

So, the proper answer is option A. Trophozoite.

Note: The trophozoite state is often confused with cysts; the difference being that cysts are thick-walled rigid structures while trophozoites are often thin and delicate. They are usually smaller, measuring about an average of twenty percent of the diameter of the red blood corpuscle.