Question

define cell theory? Who discovered it and in which year

Answer 1

cell theory was proposed by schleiden and Schwann in 1938 and 1939

Answer 2

The cell theory was proposed by Matthias Schleiden and Theodor Schwann in 1838.

The cell theory stated -
1) Cell is structural and functional unit of life.
2) All organisms are made up of two or more cells.
3) All cells develop from pre existing cells.

Hope it helps.
Please follow.