The study of viruses is a part of biology because
a. they belong to the kingdom monera.
c. they are living organisms.
b. they are about to become extinct.
d. they are active inside living cells.

D. Viruses are not considered to be living organisms but they can function inside living cells and multiply by using things in the cells. They can cause diseases in living organism and studying them is important in the medical field.

An egg, or a sack of flour