Which correctly lists the three gases that each make up less than 1 percent of Earth’s atmosphere?

The correct answer is A. Argon, water vapor, carbon dioxide.

Explanation: Earth’s atmosphere is composed mainly of nitrogen (about 78%) and oxygen (about 21%), with argon, water vapor, carbon dioxide, and other gases making up the remaining less than 1%. Specifically, argon is approximately 0.93% of the atmosphere, water vapor varies (but typically is around 0-4%), and carbon dioxide is about 0.04%. Choices B, C, and D include gases that make up more significant portions of the atmosphere, so A is the only correct option.