Earth's earliest atmosphere was most likely composed of hydrogen, helium,
A) oxygen, and nitrogen.
B) methane, and nitrogen.
C) methane, and ammonia.
D) oxygen, and ozone.
Question 2
Earth's atmosphere probably developed from gases escaping from its interior during volcanic eruptions. This outgassing also produced Earth's
A) protective ozone layer.
B) oceans.
C) numerous mountain belts.
D) ionosphere.
