OK the the answer you are looking for will be the excretory system because that is the system that releases waste.
Answer:
Stem cell is the special type of cell that can differentiate to give any cells in the body. Cell therapy nowadays are using stem cell in order to replace damaged tissue.
Researchers are finding out ways to treat diseases like diabetes, Parkinson's, spinal cord injury and heart injury etc. These cells have the ability to repair damaged heart cells after a heart attack. They can also treat neurological problems.
The discovery of the cell was possible do to the invention of the Microscope.
