99 percent of the earth's atmosphere by mass is made up of only elements. these elements are a)carbon and oxygen b)nitrogen and oxygen c)hydrogen and oxygen d) helium and hydrogen

The correct answer is B) Nitrogen and oxygen

Explanation:

The atmosphere refers to the gaseous layer that covers a body such as a planet. The composition of the atmosphere varies according to the planet or body and therefore the elements found on it are different. In the case of our planet, the atmosphere is mainly composed of nitrogen and oxygen as these are 99% of the atmosphere, while other elements such as carbon dioxide represent the 1% missing. Also, the atmosphere is divided into different layers according to heigh this includes the troposphere, stratosphere, among others. Thus, 99 percent of the Earth's atmosphere is made up only of nitrogen and oxygen.

i think it would be 5