Natural Science CLEP Prep Practice Exam

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Prepare for the CLEP Natural Science Exam with our comprehensive study materials and practice questions. Test your knowledge and ace the exam by mastering key concepts.

Each practice test/flash card set has 50 randomly selected questions from a bank of over 500. You'll get a new set of questions each time!

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What is the main gas found in Earth's atmosphere?

Helium
Nitrogen
Carbon Dioxide
Oxygen

The correct answer is: Nitrogen

Nitrogen is the most abundant gas found in Earth's atmosphere, making up approximately 78% of the total composition. Helium is only a trace gas, making up less than 1% of the atmosphere. Carbon dioxide is also a trace gas, with a concentration of around 0.04%. Oxygen, although essential for life, only makes up about 21% of the atmosphere. Therefore, B is the main gas found in Earth's atmosphere.