Question

What is cell theory? Who propounded it and when?

Answer 1

the cell theory was first discovered by two german biologist M.I schlinden in 1838, a botanist T. schwan according to them , the cell is structural and functional  unit of living beings. 

Answer 2

in 1838, a German botanist , m.j.schleiden and in 1839 a German zoologist Theodor Schwann , after studying plants and animals independently put forward a theory called the cell theory .it states that 1. all the living organism, whether plants or animals are made up of cells. 2. Rudolf Virchow in 1858 said ' omnis cellula-e-cellula' meaning all cell arise from pre-existing cell.this was also incorporated in the cell theory later on.