Skin serves as a protective barrier, a way to sense the world, and a layer that keeps nutrients and water inside the body. Four types of cells make up the skin, and they are produced mainly in the epidermis near the basement membrane.
Prokaryotes reproduce asexually by binary fission; they can also exchange genetic material by transformation, transduction, and conjugation.
Water enters the soil in a process called infiltration, and then moves downward through the soil in a process called percolation.
