What are the principles of cell theory? Describe it.

The cell theory was given by Matthias Schleiden and Theodor Schwann in 1839, which was later modified by Rudolf Virchow.

The three principles of the cell theory are:

1. Every living organism is made up of one or more cells and products of cells.
2. The smallest living organisms are single cells that are unicellular and cells are the functional units of multicellular organisms.
3. All cells arise from pre-existing cells.

Meanwhile,

1. All cells are either prokaryotic or eukaryotic.
2. Prokaryotic cells, or bacteria, are small and relatively simple in structure.
3. More complex eukaryotic cells make up all other forms of life like protists, fungi, plants, and animals.