Our food is our energy. When we eat food, we need to digest it and the eaten food, once digested, serves as our energy that we use up for daily needs. If we eat too much food, it will be store and we will become overweight over time. If we don't eat enough, we will lose weight because we're not getting enough energy in our bodies, so our bodies cannot get enough energy from the food eaten, so it looks elsewhere for stored energy - our fat and muscle cells.
The functions of eyes parts are as follows:
Retina: The rays of light focused on the retina by the cornea and lens. The retina produces an image which is sent along the optic nerve of the brain.
Iris: It changes the size of pupil and allows different amount of life to enter the eyes.
Pupil: The light enters to the eyes through it.
Cornea: It forms the outer coating of the eyeball and covers the iris and pupil.
Lens:
