Final answer:
Mitochondria are the tiny bodies within cells that produce essential energy for the cell's function, growth, and repair by creating ATP through cellular respiration.
Step-by-step explanation:
The tiny bodies within cells that supply essential energy for function, growth, and repair are known as mitochondria. These organelles are commonly referred to as the "powerhouses" or "energy factories" of a cell. They are responsible for making adenosine triphosphate (ATP), which is the cell's main energy-carrying molecule. ATP is created through the process of cellular respiration, which involves the breakdown of glucose. Mitochondria have their own ribosomes and DNA, and are enclosed by a dual phospholipid bilayer membrane with the inner membrane having folds called cristae to increase surface area.