Answer: Cell theory is a fundamental principle in biology that states:
All living organisms are composed of one or more cells.
The cell is the basic unit of structure and function in organisms.
All cells arise from pre-existing cells through cell division.
This theory was formulated by Matthias Schleiden, Theodor Schwann, and Rudolf Virchow in the mid-19th century and has since served as the foundation for understanding the organization and functioning of living organisms.
