1. All living organisms are composed of one or more cells. This means that cells are the fundamental building blocks of life, and there are no organisms that exist without them.
2. The cell is the basic unit of structure and function in living organisms. This means that all the activities necessary for life take place within cells, and they are the smallest unit that can carry out these functions independently.
3. All cells arise from pre-existing cells. This means that cells do not spontaneously generate, but rather come from the division of other cells. This idea challenged the long-held belief in spontaneous generation.
These three principles form the foundation of modern cell biology and have revolutionized our understanding of life.
