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

Give any four factors necessary for a healthy person.

Explain giving reasons:
$(a)$ Balanced diet is necessary for maintaining a healthy body.
$(b)$ The health of an organism depends upon the surrounding environmental conditions.
$(c)$ Our surrounding area should be free of stagnant water.
$(d)$ Social harmony and good economic conditions are necessary for good health.

It was diagnosed that a patient has lost the power of fighting against any infection.
$(i)$ Name the disease from which the patient is suffering.
$(ii)$ Name the pathogen responsible for the disease.

Why is $DPT$ called a Triple antigen?

State whether the following statement is true or false:
The diseases which last for only short periods of time are called chronic diseases.