Part of the current atmosphere of Earth is believed to be
a. the remnants of the original hydrogen and helium gas from the solar nebula attracted by the protoplanet.
b. the result of the melting and vaporizing of the glaciers from the last ice age.
c. composed primarily of hydrogen and helium.
d. composed of gases that were outgassed from the heated rocks sometime after the planet formed.
e. the result of a collision between the Sun and another star.
Question 2
If a star is found with five planets orbiting it, and a process like that described in the solar nebula theory formed the planets, which of the planets would be expected to have the greatest uncompressed density?
a. The one farthest from the star.
b. The one with the greatest mass.
c. The one with the greatest radius.
d. The one closest to the star.
e. The one that has liquid water on its surface.