Which option correctly lists the three classical tenets of cell theory?

• A. All living things are composed of cells; mitochondria are the powerhouse of the cell; all cells contain identical DNA.
• B. All living things 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.
• C. Cells are the basic unit of heredity; all enzymes are proteins; all cells arise from pre-existing cells.
• D. All cells contain a nucleus; all organisms are multicellular; all cells arise spontaneously from nonliving matter.

Answer: (B)