Question

The protozoans that cause malaria in humans are
 A. Trichosomes
B. Dinoflagellates
C. Sporozoans
D. Radiolarians

Answer 1

Hint: Malaria is a disease caused by a parasite. It is a mosquito-borne disease that poses threat to life. Malaria transmission occurs through the bite of a female Anopheles mosquito infected with parasites. When this infected mosquito bites human beings, it releases parasites into the stream of blood.

Complete answer:
Plasmodium is a sporozoan belonging to phylum protozoa. It causes malaria, which is a fatal disease. Various species of Plasmodium responsible for spreading malaria are: Plasmodium vivax, Plasmodium falciparum, Plasmodium malariae, and Plasmodium ovale.
Infected female Anopheles mosquitoes usually bite human beings during the dusk and dawn thus transmitting the disease malaria.
The life cycle of malaria:
The malaria parasite known as Plasmodium is injected into the bloodstream of a person through the bite of an infected female Anopheles mosquito. The injected Plasmodium is in the form of sporozoites.
These sporozoites attack the human liver and multiply by asexual mode of reproduction.
These sporozoites are converted into another form of parasite known as merozoites. These merozoites are then released into the capillaries of the lungs thus entering into the blood where they attack the red blood corpuscle and multiples.
These merozoites reproduce sexually forming gametocytes that are ingested forming mature cells known as gametes. These gametes then carry out the further process and this cycle continues each time a mosquito bites an individual.

Hence, the correct answer is option (C).

Note: Sporozoans are microbes with no flagella or cilia. These are parasitic in nature and usually transmitted through a vector. Plasmodium falciparum is the most common protozoan known to cause malaria which is characterized by fever, headache, chills, vomiting, and nausea.