1. All living organisms are composed of one or more cells. This means that cells are the fundamental building blocks of all life, from the smallest bacteria to the largest animals.

2. The cell is the basic unit of life. This means that cells are the smallest unit that can carry out all the processes necessary for life, such as metabolism, reproduction, and response to stimuli.

3. All cells arise from pre-existing cells. This means that cells do not spontaneously generate, but instead come from the division of other cells.