As scientists began investigating living things and their cellular structure, they developed a set of principles that are now known as the cell theory. The statements below summarize cell theory.

• All living things are made up of cells.
• Cells are the basic units of structure and function in living things.
• New cells are produced from existing cells.

What was the role of microscopes in the development of cell theory?

A. Cell theory relied on the invention and improvements in the light microscope, which allowed scientists to identify cells.
B. Cell theory relied on the invention of electron microscopes, which allowed scientists to identify and describe cellular structures.
C. Cell theory was developed independently of microscopes, but scientists today use microscopes to confirm the theory.
D. Cell theory is unrelated to microscopes because cells can be observed and studied with the unaided eye.