In the history of cell biology, which option correctly lists the three classic tenets of cell theory?

• A. All living organisms are composed of one or more cells; the cell is the basic unit of structure and function in living things; all cells arise from pre-existing cells.
• B. All cells contain a nucleus; all cells contain mitochondria; all cells have a rigid cell wall.
• C. Cells can arise spontaneously from nonliving matter; the nucleus is the basic unit of life; organisms are composed only of tissues.
• D. All organisms are made of molecules; the atom is the basic unit of life; new organisms arise only from genetic recombination.

Answer: (A)