Distinguish between Virion and Viroid.

A baby is suffering from diarrhoea, while other babies in the same locality do not. Mention the possible causes that you think. What would be the possible solutions for this?

Name the vector of the malarial parasite. Mention the species of malarial parasite which cause malignant and fatal malaria.

What is triple antigen? Mention the disease which can be prevented by using the antigen.

Sanjay had an attack of chicken pox and has just recovered. The health officer of his locality says that the disease would not occur again for him. What would be the reason for this?