Motile zygote of Plasmodium occurs in:

Explanation

Plasmodium, a tiny protozoan parasite causes malaria in humans and is transmitted through the bite of an infected female Anopheles mosquito. When female Anopheles sucks the blood of an infected human it takes up gametocytes (sexual stages of parasite) 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 a worm-like motile organism called an ookinete. Ookinete further changes into sporozoites(mature infective stage of Plasmodium).