Viruses,which cause hepatitis,are transmitted through

Given below are a few situations:
$(i)$ Geeta of Class $IX$ was having a common cold. She sits with Sarika,who also develops the disease.
$(ii)$ Animesh of Class $IX$ shifted to a new residence with his family where a water purification system has not been installed yet. He develops Cholera and Dysentery.

How does the $HIV$ virus affect the body and kill the affected person?

Name any three diseases transmitted through vectors.

We should not allow mosquitoes to breed in our surroundings because they :

Which one of the following diseases is not transmitted by mosquitoes?