Once upon a time, there was a scientist named Robert Hooke.

Robert was studying different things using his microscope, and had a great idea!

"What if I look at cork under a microscope?" Robert said.

Robert couldn't believe it! The cork had small patterns inside of it!

"I'm going to call this a cell," Robert exclaimed.

Soon, another scientist named Robert Brown entered the room.

Robert Brown wanted to look with the microscope too!

He looked closely, and found an even smaller part of the "cell".

"I'm going to call this the nucleus!" Robert Brown said.

Robert Hooke and Robert Brown decided to invite their friend Rudolph Virchow over to hear the news.

Rudolph looked into the microscope. He was amazed!

He told the other scientists that he had an idea.

"I think that all cells come from cells that already exist," Rudolph declared.

The other scientists agreed! They then came up with two more theories...

"Cells make up every organism! They give structure to the organism."

"All organisms are made up of one or more cells!"

The scientists quickly spread the news to everyone. Today, we call these ideas THE CELL THEORY.

THE END