In the 1800s, two scientists studied different types of organisms under the microscope. They discovered the following: Schwann studied animal and found that they were made of cells.

Schleiden studied plants and found that they were made of cells.

Which part of the cell thoery did both of them contribute?

All cell require oxygen for life.

Cells are the smallest whole unit of life.

All living things are made of cells.

Cells come from other cells.