In the history of cell biology, which option correctly lists the three classical 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 organisms; all cells arise from pre-existing cells.
• B. All cells contain a nucleus; all cells are surrounded by a cell wall; all cells arise spontaneously from nonliving matter.
• C. Cells are the basic unit of heredity; all organisms are multicellular; all cells arise from free ribosomes in the cytoplasm.
• D. All living organisms are composed of atoms; the atom is the basic unit of life; all atoms arise from pre-existing atoms.

Answer: (A)