In 1838 botanist Matthias Schleiden determined that all plants are composed of cells. In 1839 anatomist Theodor Schwann proposed that all animals are composed of cells. In 1855 biologist Rudolph Virchow added to Schleiden’s and Schwann’s observations and proposed that all living things are composed of cells. Which statement is also part of Virchow’s cell theory?
All cells can develop into any other type of cell.
All cells are capable of photosynthesis.
All cells arise from pre-existing cells.
All cells have a cell wall.