1. All living things are composed of one or more cells. This is the foundation of cell theory. Every organism, from the simplest bacteria to the most complex human, is made up of cells.
2. The cell is the basic unit of life. Cells are the smallest units that can carry out all the functions necessary for life, such as metabolism, reproduction, and response to stimuli.
3. All cells arise from pre-existing cells. This means that new cells are not spontaneously generated; they always come from the division of other cells. This principle helps explain the continuity of life across generations.
