Earth's atmosphere has been oxygen-rich for __________ of Earth's history.
A)approximately 25%
B)approximately 50%
C)approximately 75%
D)approximately 99%

Name: Earth's atmosphere has been oxygen-rich for __________ of Earth's history. A)approximately 25% B)approximately 50% C)approximately 75% D)approximately 99%
Brand: Quizplus
Rating: 4.9 (36 reviews)

Question

Quizplus · Accepted Answer

The Answer of Earth's atmosphere has been oxygen-rich for __________ of Earth's history.
A)approximately 25%
B)approximately 50%
C)approximately 75%
D)approximately 99%

Earth's Atmosphere Has Been Oxygen-Rich for __________ of Earth's History