Final answer:
Approximately 1 percent of the Earth's atmosphere is made up of elements other than nitrogen and oxygen.
Step-by-step explanation:
The correct answer is 1 percent. The Earth's atmosphere is composed mainly of nitrogen (78%) and oxygen (21%). The remaining 1% consists of various other gases including carbon dioxide, argon, and trace amounts of water vapor, methane, and ozone.
Learn more about Composition of Earth's atmosphere