You caught the ball, but you ran the wrong direction. It gets into your body and makes you sick. Dr. Del Rio sighed impatiently. Your body is made up of millions of cells, and each of these cells performs a certain function. Terry said nothing, and he continued.
Every cell is basically a tiny living creature.
Your body is basically a colony of little, tiny animals, all working together to sustain a larger organism. Left alone, a cell grows, takes food, passes waste, reproduces, and eventually dies. And then we have viruses. Strictly speaking, a virus is not a living entity. A virus is a piece of microscopic dust - a strip of either DNA or RNA covered with a layer of proteins.