The most common gas people breathe from clean air is nitrogen. Air is a mixture of gases, and the air on Earth contains about 78 percent nitrogen and about 21 percent oxygen. Argon, carbon dioxide neon, helium, methane, krypton, hydrogen and xenon are in much smaller amounts.
Everyday Science Mcqs. Here you will find the General Science Multiple Choice Questions Mcqs are from Biology, Chemistry, Physics and Atmospheric Studies. Everyday Science Online Test 2 Mcqs Preparation Practice Questions. All Important Abbreviation related to Everyday Science in MCQs. General Science mcqs and Scientific facts MCQs. Everyday Science MCQs with Answers.