Which element is more plentiful on Earth?

• A. Hydrogen
• B. Carbon
• C. Oxygen
• D. Nitrogen

Answer: (C)

Verified step by step guidance

1. Begin by understanding the context of the question: it asks which element is more plentiful on Earth, not in the universe or any other context.
2. Consider the composition of the Earth's crust, atmosphere, and oceans, as these are the major reservoirs of elements on Earth.
3. Oxygen is a major component of the Earth's crust, primarily found in the form of oxides such as silicon dioxide (SiO₂) and other minerals.
4. In the atmosphere, oxygen is the second most abundant element after nitrogen, making up about 21% of the air by volume.
5. Oxygen is also a significant component of water (H₂O), which covers about 71% of the Earth's surface, further contributing to its abundance.