3. a. A balloon filled with carbon dioxide falls to the ground but a balloon filled with He floats away because the of a gas increases as the increases.

Why does earth rotate? because earth is formed from cold gases collapsing due to gravity because the matter in the nebula that formed earth was spinning because earth forms more than 99% of the mass of the solar system because the hydrogen atoms inside the nebula fused to form helium

Which terms are used to identify pure substances

At element makes up all organic compounds?