Question

question 3
1 pts
approximately how much of our atmosphere is oxygen?
78%
100%
1%
21%

Explanation:

The Earth's atmosphere is composed of various gases. Nitrogen makes up about 78%, oxygen about 21%, and other gases (including argon, carbon dioxide, and trace gases) make up approximately 1%. So, the percentage of oxygen in the atmosphere is known through scientific study of atmospheric composition.

Answer:

21%