ECOLOGY
CHEMICAL CYCLES
|
Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
|
What percent of the atmosphere is oxygen?
|
|
30%
|
|
|
21%
|
|
|
2.2%
|
|
|
14%
|
Explanation:
Detailed explanation-1: -The air in Earth’s atmosphere is made up of approximately 78 percent nitrogen and 21 percent oxygen.
Detailed explanation-2: -Earth’s atmosphere is composed of about 78% nitrogen, 21% oxygen, and one percent other gases.
Detailed explanation-3: -In fact, the troposphere contains three-quarters of the mass of the entire atmosphere. The air here is 78% nitrogen and 21% oxygen. The last 1% is made of argon, water vapor, and carbon dioxide.
Detailed explanation-4: -By 600 million years ago, the oxygen in the atmosphere reached about one-fifth of today’s level (21 percent).
There is 1 question to complete.