Robert Hooke was examining a piece of cork under a microscope, when he discovered that it was made of many little structures. The small structures were packed together and reminded him of monk's cells. Therefore, he decided to call the small structures cells!
I will name them cells!
Every cell has this same little dot floating within it. I will call it the nucleus.
Robert Brown was examining cells, when he discovered that each one of them contained a small dot. He decided to name those small dots the "nucleus."
Theodore Schwann was a German Physician. He was examining animal tissue when he noticed, that the tissue was made of cells. After more research he discovered that all animals are made of cells.
Even animals contain cells? Each and every animal is made of cells.