Question

which gases each make up less than 1 percent of earth’s atmosphere

Answer 1

Nitrogen is the answer, I think so

Answer 2

Gases like Argon, nitrous ixide, ozone, carbon dioxide, methane and trace gases together constitute less than 1 percent of earth’s atmosphere.

Water vapor is also there in earth's atmosphere from 0 to 4 percent and its concentration depepnds on where a person is situated and what time of the day it is over there.

Apart from them, Nitrogen and Oxygen are the major gases in the atmosphere.

There is 78 percent nitrogen and 21 percent of oxygen in the atmosphere.