1. Which gas is most abundant in Earth's atmosphere? 2. Which blood cells carry oxygen? (Q18) 3. Which metal is liquid at room temperature? (Q94) 4. Which organ pumps blood in the human body? 5. Which gas do plants absorb during photosynthesis? 6. Which metal is liquid at room temperature? (Q59) 7. Which planet is known as the Red Planet? (Q62) 8. Which metal is liquid at room temperature? (Q99) 9. Which gas do plants absorb in photosynthesis? (Q20) 10. Which blood cells carry oxygen? (Q33)