The appearance of signs of sexual maturity on the outside of the body, such as growth of underarm hair is known as

stratosphere: as the altitude increases, the air temperature increases. the stratosphere has a layer of ozone, called the ozone layer. this layer absorbs most of the ultraviolet radiation from sunlight. this results in the stratosphere being warmer.

"a.) well–developed vascular system."

the answer is c. it will give up it's valence electron to the other atom.