When Life First Began

Multiple Choice

When life first began,

A) the planet had a lot of oxygen in the atmosphere and was much warmer.
B) the planet had a lot of oxygen in the atmosphere and was much cooler.
C) the planet had a lot of methane in the atmosphere and was much warmer.
D) the planet had a lot of methane in the atmosphere and was much cooler.
E) the planet had very little oxygen in the atmosphere and was much cooler.