Olfactory cells play a role in sensing smells in the nose.

Neurons are responsible for transmitting information in the brain.

Macrophages play a role in taking in and breaking down foreign substances in the body.

Oocytes play an important role in the reproduction of organisms.

Multicellular organisms, unlike unicellular organisms, have specialized cells in their bodies that perform functions.

His constitution makes him prone to catching colds.

He has a susceptibility to depression, and tends to get down over little things.

He has cyclothymia, and his mood changes drastically.

The aerosol in this area is very dense.

That dog is reputed to be vicious.