Why is nothing in nature truly pure?

Which phrases describe oxygen's roles in earth’s atmosphere? check all that apply. allows fuels to burn forms clouds that produce rain is the gas that animals breathe is used by plants to produce food forms ozone that absorbs the sun's harmful rays

Following lenins death, who took control of the soviet union

As stress on rock increases, the energy stored in it a.) decreases b.) melts c.) increases d.) disappears