Give any four reasons to justify why it is more difficult to prepare antiviral medicines than antibiotics.

What is inflammation? Write the symptoms of this in the human body.

$(a)$ Which part of the body is infected by the malaria-causing microbe?
$(b)$ What are the two ways to treat an infectious disease?

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.

Distinguish between acute and chronic diseases.

Name two types of diseases caused by regularly breathing in the polluted air.