Hi! I'm Matthias Schleiden, a german botanist, who cofounded the cell theory together with Theodor. I defined that cell is the basic unit of plant structure.
I'm Theodor Schawnn, a german physiologist who proposed the cell theory with Matthias. All the plant and animals tissus are composed of cells and within an individual organism all the cells are identical.
I'm Carl Heinrich Braun. The cell theory defining cells are the basic unit of life.
The discovery of nucleus and its role helped to placed together the cell theory, which states that each one living organisms are composed of cells, and cells come from pre-existing cells. Brown's discovery helped substantiate the half of the cell theory.