Motile zygote of Plasmodium occurs in the gut of female Anopheles mosquito.

Explanation:
Plasmodium is a protozoan parasite that causes malaria in humans. It has a complex life cycle that involves two hosts: humans and female Anopheles mosquitoes. The life cycle of Plasmodium consists of two phases: the asexual phase that occurs in the human host and the sexual phase that occurs in the mosquito host.

In the human host, Plasmodium infects the red blood cells and undergoes asexual reproduction, resulting in the formation of merozoites. These merozoites then infect other red blood cells and continue the cycle. However, when a female Anopheles mosquito bites an infected human, it ingests the gametocytes (male and female) of Plasmodium along with the blood.

Inside the mosquito's gut, the gametocytes of Plasmodium undergo sexual reproduction to form a motile zygote. The motile zygote then develops into an ookinete, which penetrates the mosquito's gut wall and develops into an oocyst. The oocyst then undergoes multiple divisions to form sporozoites, which migrate to the mosquito's salivary glands.

When the infected mosquito bites another human, the sporozoites enter the human host and infect the liver cells, resulting in the formation of merozoites. These merozoites then infect the red blood cells and cause malaria.

Therefore, the motile zygote of Plasmodium occurs in the gut of the female Anopheles mosquito.