Cell theory was proposed by MJ Schleiden , T.Schwann and Rudolf Virchow.
Cell theory states that, all organisms are made up of cells, Cell is the structural and functional unit of life and Cells arise from pre-existing cells.
In ancient time there was a concept of spontaneous existence of life.
People believed that life arose from inorganic substances.
But when Fransesco Redi observed that maggot arose on meat.
He hypothesised that the maggot must have risen from fly egg.
To confirm this hypothesis he set up an experiment in which he kept meats in flasks; some open to air, some covered with gauge and some completely sealed.
It was obvious that the sealed flask will not support life as it does not have air .
The flask covered with gauge proved that the concept of evolution of life from inorganic substance was wrong because the flask had all the inorganic elements that support life like air water light etc but no maggots grew in it.
The open flask , in which the maggots grew proved that maggots arose from the eggs that were laid by the fly.
Only the open flask had provisions for the fly to enter it and lay eggs. These eggs were the first cell of the maggot.
Thus, Redi's Experiment supported the fact that cells arise from preexisting cells.
