Which statement is part of the cell theory?

• A. Cells are the smallest unit of life capable of photosynthesis.
• B. Cells can spontaneously generate from non-living matter.
• C. All living organisms are composed of cells.
• D. Cells are the only organisms that can reproduce sexually.

Answer: (C)

Verified step by step guidance

1. Begin by understanding the historical context of the cell theory, which was developed in the mid-19th century by scientists like Matthias Schleiden, Theodor Schwann, and Rudolf Virchow.
2. Recognize the three main components of the cell theory: 1) All living organisms are composed of one or more cells, 2) The cell is the basic unit of life, and 3) All cells arise from pre-existing cells.
3. Evaluate each statement given in the problem against the components of the cell theory. The statement 'All living organisms are composed of cells' directly aligns with the first component of the cell theory.
4. Consider the statement 'Cells can spontaneously generate from non-living matter.' This contradicts the third component of the cell theory, which states that cells arise from pre-existing cells, not spontaneously from non-living matter.
5. Analyze the statement 'Cells are the only organisms that can reproduce sexually.' This is incorrect because not all cells reproduce sexually; many reproduce asexually, and sexual reproduction involves multicellular organisms.