Malaria is caused by ...............

In $Plasmodium$ $vivax$,fertilization occurs in:

Assertion $A$: $A$ patient suffering from malaria becomes pale and weak.
Reason $R$: $Plasmodium$ causes the breakdown of hemoglobin and destruction of red blood cells $(RBCs)$.
Which option is correct for Assertion $A$ and Reason $R$?

The signet ring stage of $Plasmodium$ represents:

Enteritis, a widespread disease in India, is caused by the infection of:

Who discovered the malarial parasite?