In the history of cell biology, which set 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 living things; all cells arise from pre-existing cells.
• B. All cells contain a nucleus; all organisms are multicellular; cells arise spontaneously from nonliving matter.
• C. All living organisms are composed of tissues; the tissue is the basic unit of life; all tissues arise from pre-existing tissues.
• D. Cells are the basic unit of heredity; all cells arise only from abiotic chemicals; all organisms are composed solely of proteins.

Answer: (A)