The correct answer is: All cells arise from pre-existing cells.
Rudolf Virchow was a German physician and biologist who proposed the idea that all cells come from the division of pre-existing cells in 1855. He coined the phrase "omnis cellula e cellula", which means "every cell from a cell" in Latin. He based his idea on the observations of other scientists, such as Robert Remak and Theodor Schwann, who had shown that cells divide and multiply by mitosis. Virchow's idea was a major contribution to the cell theory, which states that:
- All living things 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.
The other options are incorrect because:
- All cells do not have a thick coating around them. Some cells have a cell wall, which is a rigid layer that provides support and protection, while others have a cell membrane, which is a flexible layer that controls what enters and exits the cell. Some cells have both a cell wall and a cell membrane, while some have neither.
- The cell is not the largest unit of structure to an organism. The cell is the smallest unit of structure that can perform all the functions of life. Organisms can be composed of one or more cells, and multicellular organisms have different levels of organization, such as tissues, organs, organ systems, and organisms.