Cell Theory

The Cell Theory is composed of three parts:

1. All organisms are composed of one or more cells

2. The cell is the basic unit of structure and organization in organisms

3. All cells come from pre-existing cells

The Cell Theory helps us understand that when a virus attacks a part of the body, it is attacking the cells in that part of the body, because all organisms are made up of cells, so every part of the human body is made up of cells.