Hey Sweetie! I'll gladly answer this question for you! I'll give you the answer....
Here it is: The right answer is the option B. Close to 99 percent. The atmosphere is a mixture of gases: nitrogen, oxygen, CO2, H2O, argon, among others. Nitrogen is about 78% and oxygen is about 21%, so they two together constitute about 99 percent of the Earth's atmosphere.
78% of nitrogen, 21% oxygen, and 1% of carbon dioxide and other gases.
Hope I helped you!
