Which two biologists presented cell theory? State the theory given by them. 
 

Solution:

• The cell theory was proposed by two scientists- Schleiden (1838)and Schwann (1839).
• It says that all the plants and animals are composed of cells and the cell is the basic unit of life.

Key points of the cell theory are as follows:

• All known living things are made up of one or more cells.
• All cells arise from pre-existing cells by division.
• The cell is the fundamental unit of structure and function in all living organisms.

The cell theory was further expanded by Virchow (1855) by suggesting that all cells arise from pre-existing cells.