Which gas is most abundant in Earth's atmosphere?
Difficulty: Easy
About this MCQ
This Easy Everyday Science MCQ checks one syllabus fact. Candidates use it for NTS GAT General practice.
The question is: “Which gas is most abundant in Earth's atmosphere?”
The accepted answer is C. Nitrogen. Dry air is approximately 78% nitrogen (N2), 21% oxygen (O2), and 1% other gases including argon and carbon dioxide.
- A. Oxygen
Why not A: Oxygen is about 21% of the atmosphere.
- B. Carbon dioxide
Why not B: CO2 is only a trace gas (~0.04%).
- C. Nitrogen ✓
- D. Hydrogen
Why not D: Hydrogen is present only in very small amounts in the lower atmosphere.
Correct answer
C. Nitrogen
Explanation
Dry air is approximately 78% nitrogen (N2), 21% oxygen (O2), and 1% other gases including argon and carbon dioxide.
Source: Atmospheric science basics
Tags: Physics, Chemistry
Relevant exams: NTS GAT General
Submitted by: MCQsHub Editorial
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