Science 8 · Unit 5: Materials and cycles on Earth · Cambridge Lower Secondary Science Stage 8

Questions

1. 1. What produced the early atmosphere?

   • people
   • volcanoes
   • plants
   • oceans
   Check

2. 2. Which gas made up most of the early atmosphere?

   • carbon dioxide
   • oxygen
   • nitrogen only
   • helium
   Check

3. 3. Which planet's atmosphere is like Earth's early atmosphere?

   • the Moon
   • Venus
   • Saturn
   • Jupiter
   Check

4. 4. How did the oceans form?

   • Water vapour from volcanoes condensed.
   • Plants made water.
   • Rivers made them.
   • Ice melted from space.
   Check

5. 5. How did plants change the atmosphere?

   • They added nitrogen.
   • They removed oxygen.
   • They used carbon dioxide and released oxygen by photosynthesis.
   • They released carbon dioxide only.
   Check

6. 6. Where did much of the carbon from early carbon dioxide end up?

   • locked up in fossil fuels and carbonate rocks like limestone
   • in the Sun
   • in the Moon
   • in clouds only
   Check

7. 7. What is the percentage of carbon dioxide in the atmosphere today?

   • about 80%
   • about 0.04%
   • about 4%
   • about 40%
   Check

8. 8. What has happened to carbon dioxide levels over the past 200 years?

   • They have fallen.
   • They have risen.
   • They have stayed the same.
   • They have reached zero.
   Check

9. 9. Why have carbon dioxide levels risen recently?

   • The oceans have dried up.
   • More volcanoes erupt.
   • Plants make more carbon dioxide.
   • People burn fossil fuels.
   Check

10. 10. What is global warming?

    • the Sun getting bigger
    • hot summers only
    • the rise in Earth's average temperature
    • a warm day
    Check

11. 11. What evidence supports global warming?

    • fewer clouds one day
    • one cold winter
    • rising average temperatures, melting ice and rising sea levels
    • more rain in one town
    Check

12. 12. Why are the last 100 years of temperature records more reliable than earlier evidence?

    • It was warmer.
    • People guessed better.
    • There were fewer people.
    • They were measured directly with accurate instruments.
    Check

13. 13. How did carbon dioxide change from 4500 to 1500 million years ago?

    • It disappeared then returned.
    • It stayed the same.
    • It decreased a lot.
    • It increased.
    Check

14. 14. Which gas makes up most of the atmosphere today?

    • oxygen
    • argon
    • nitrogen
    • carbon dioxide
    Check

15. 15. What is the rock limestone mostly made of?

    • carbon dioxide gas
    • calcium carbonate
    • iron
    • quartz
    Check

16. 16. Which evidence shows that the amount of oxygen in the atmosphere rose?

    • bands of red iron oxide in old rocks
    • ice at the poles
    • volcanoes that erupt today
    • fossils of fish
    Check

17. 17. What percentage of today's atmosphere is nitrogen?

    • about 0.04%
    • about 78%
    • about 95%
    • about 21%
    Check

18. 18. Which of these is a renewable energy resource?

    • natural gas
    • coal
    • the wind
    • petroleum
    Check

19. 19. What is one problem with generating electricity from wind turbines?

    • They give off carbon dioxide.
    • They only work when the wind blows.
    • They only work at night.
    • They burn fossil fuels.
    Check

20. 20. What are bioplastics made from?

    • metal ores
    • coal
    • petroleum
    • renewable materials such as vegetable oils or food waste
    Check