Question

Which mixture of gases is thought to have made up Earth's early atmosphere?
A. methane, oxygen, hydrogen, water vapor B. carbon dioxide, nitrogen, oxygen, ozone
C. hydrogen, water vapor, ammonia, methane, carbon dioxide D. ozone, water vapor, carbon dioxide, ammonia

Answer 1

option C. is the answer

Answer 2

(4.6 billion years ago)

As Earth cooled, an atmosphere formed mainly from gases spewed from volcanoes. It included hydrogen sulfide, methane, and ten to 200 times as much carbon dioxide as today's atmosphere.