Amoebiasis is caused by

For further development, the sporozoite must enter into the:

The incubation period of $Plasmodium$ $vivax$ is ........

Gametogenesis in $Plasmodium$ occurs in:

Fever in malaria is due to

Assertion $A$: $Plasmodium$ is a microscopic protozoan.
Reason $R$: Humans and female $Anopheles$ mosquitoes are the hosts of $Plasmodium$.
Which option is correct for Assertion $A$ and Reason $R$?