Inventing the first truly compound microscope.
Robert created a newer version of the first microscope. He created the second microscope.
Anton van Leeuwenhoek was the first scientist to closely observe cells under a microscope
Theodor also helped with the cell theory. He said all animals are made of cells.
Shleiden help developed the cell theory. He said all plants are made of cells.
He helped determine the states of the cell theory. Which are, all living things are composed of cells, cells are the basic units of structure and function in living things, all cells are produced from other cells. He came up with the last cell theory