Home  >  8th Grade Science  >  ITBS Level 14 Grade 8 Science 6

For the first few billion years of the Earth's history, there was almost no molecular oxygen in the atmosphere. Now, the atmosphere is about 21 percent oxygen by volume. What is the primary factor that caused this change?

🎲 Try a Random Question  |  Total Questions in Quiz: 24  |  🧠 Study this quiz with Flashcards
This question is part of a full practice quiz:
ITBS Level 14 Grade 8 Science 6 — practice the complete quiz, review flashcards, or try a random question.
🧠 Flashcards (fast review) 🧪 Practice Quiz ⚔️ Challenge a Friend 🥊

For the first few billion years of the Earth's history, there was almost no molecular oxygen in the atmosphere. Now, the atmosphere is about 21 percent oxygen by volume. What is the primary factor that caused this change?






 
❤ If you liked Fatskills, consider supporting us by checking out The Life Manuals You Never Got.

🌈  Our mission is to help improve your scores in any subject and exam withonline quizzes, practice tests, study guides, & advice for students. Since 2018.
About | Explore | User Guide | Topics | Subjects | Doubt Solver | Career Aptitude Test | Answers | Free Tools | What Should We Know?
Privacy | Terms |
Without work one finishes nothing. - Ralph Waldo Emerson
© 2026 Fatskills.com

All trademarks, logos and brand names are the property of their respective owners. All company, product and service names used in this website are for identification purposes only. Use of these names, trademarks and brands does not imply endorsement.