(a) : Plasmodium, a tiny protozoan parasite causes malaria in humans, and is transmitted through the bite of infected female Anopheles mosquito. When female Anopheles sucks the blood of infected human it takes up gametocytes (sexual stages ofparasite) with blood meal. The gametocytes come out of the $RBCs$ into the lumen (cavity) of the stomach of the mosquito. In the stomach, the male gametocyte divides and forms $6$ to $8$ long, motile, whip­like microgametes (male gametes). The female gametocyte does not divide but undergoes a process of maturation to become the macrogamete (female gamete). A microgamete penetrates a macrogamete and fertilization (syngamy) takes place, resulting in the formation of a zygote. The zygote elongates and becomes worm like motile organism called ookinete. Ookinete further changes into sporozoites (mature infective stage of Plasmodium).