Answer:
Cells are so little, so they can maximize their ratio of surface area to volume.
Explanation:
Smaller cells have a higher ratio which allows more molecules and ions to move across the cell membrane per unit of cytoplasmic volume. Cells are so small because they need to be able to get the nutrients in and the waste out quickly.
Because skin falls off, or are you talking bout why don't people stick together?
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:
I cannot see the imagine very well would you mind taking another?