Fire is transformation. Our digestion, metabolism of food into energy, vision, and temperature are all aspects of the element of fire.
Earth is solidity and structure and holds all living creatures on the planet. In our bodies it’s connected to our bones, muscles, hair, teeth, and nails. All mechanical energy is due to the element of earth.
Everything moves because of the element of air. It’s electrical energy and prana. Air allows all the movement in our bodies including the muscles of the heart, lungs and intestines.
Water is flow, moistness, and protection. All biochemical functions are ruled by water. Both our planet and ourselves are 70% water.