Answer:
Its main function is to act as a barrier to protect the body from the outside world. It also functions to retain body fluids, protect against disease, eliminate waste products, and regulate body temperature.
Explanation:
Answer: a hard sedimentary rock, composed mainly of calcium carbonate or dolomite, used as building material and in the making of cement.
Perhaps the world's most famous early human ancestor, the 3.2-million-year-old ape "Lucy" was the first Australopithecus afarensis skeleton ever found, though her remains are only about 40 percent complete (photo of Lucy's bones). Discovered in 1974 by paleontologist Donald C.
