1. All living organisms are composed of one or more cells. This means that everything from a single-celled bacterium to a complex human being is built from cells.
2. The cell is the basic unit of structure and function in all living organisms. This means that all the processes of life, like metabolism, growth, and reproduction, occur within cells.
3. All cells arise from pre-existing cells. This means that cells don't spontaneously appear; they come from other cells that have divided.
Essentially, cell theory tells us that all life, as we know it, is organized around the cell as the fundamental building block.
