Which element makes up most of Earth's atmosphere?

• A. Argon
• B. Oxygen
• C. Nitrogen
• D. Carbon dioxide

Answer: (C)

Verified step by step guidance

1. Understand that Earth's atmosphere is composed of several gases, with some present in much larger amounts than others.
2. Recall the major components of dry air by volume: Nitrogen (N\_2), Oxygen (O\_2), Argon (Ar), and Carbon dioxide (CO\_2), among others.
3. Recognize that Nitrogen makes up approximately 78% of the Earth's atmosphere, making it the most abundant element by volume.
4. Note that Oxygen is the second most abundant gas at about 21%, Argon is around 0.93%, and Carbon dioxide is roughly 0.04%.
5. Therefore, the element that makes up most of Earth's atmosphere is Nitrogen.