Mitochondria are tiny organelles inside cells that are involved in releasing energy from food.This process is known as cellular respiration. It is for this reason that mitochondria are often referred to as the powerhouses of the cell. Cells that need a lot of energy, like muscle cells, can contain thousands of mitochondria.
They all have different compositions of protons, neutrons, and electrons. This causes variety and makes atoms different so they can make up different substances
