Which option correctly lists the three classical tenets of cell theory as formulated in the 19th century?

• A. All organisms are composed of tissues; tissues are the basic unit of life; tissues arise from pre-existing tissues.
• B. Cells are smaller than atoms; cells spontaneously arise from nonliving matter; cells do not require energy to function.
• C. All cells contain a nucleus; all cells have a cell wall; all cells photosynthesize to produce energy.
• D. 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.

Answer: (D)

Verified step by step guidance

1. Recall the historical development of cell theory in the 19th century, which established fundamental principles about cells as the basis of life.
2. Identify the three classical tenets of cell theory: (1) All living organisms are composed of one or more cells, (2) The cell is the basic unit of structure and function in living things, and (3) All cells arise from pre-existing cells.
3. Compare each option given in the problem to these three tenets to determine which one matches exactly.
4. Note that the correct option must emphasize living organisms being made of cells, the cell as the fundamental unit, and the origin of cells from other cells, excluding incorrect statements about tissues, atoms, or cell components like nuclei or cell walls.
5. Conclude that the option stating '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' correctly lists the classical tenets of cell theory.