Final answer:
The Cell Theory states that all living things are made up of cells, and cells always come from other living cells.
Step-by-step explanation:
The Cell Theory is one of the fundamental theories of biology. It states that all living things are made up of cells, which are the structural units of living organisms. Moreover, living cells always come from other living cells. The Cell Theory was proposed by several scientists, including Theodor Schwann, Matthias Jakob Schleiden, and Rudolf Virchow.