1. All living organisms are composed of one or more cells. This means that the cell is the fundamental unit of life.

2. The cell is the basic unit of structure and function in living organisms. This means that all living things are built from cells, and the cells carry out all the functions necessary for life.

3. All cells arise from pre-existing cells. This means that new cells are not spontaneously generated, but rather they are created by the division of existing cells.