2. Which of the following is a producer?
3. Which organism is a primary consumer?
4. Which gas is most important for photosynthesis?
5. Which layer protects Earth from harmful UV rays?
7. Which of the following is a decomposer?
9. Which human activity causes deforestation?
10. Which gas causes global warming?
12. Which resource is renewable?
13. What is conservation?
14. Which level is at the top of the food chain?
15. Which cycle involves evaporation and rainfall?
16. Which pollutant causes acid rain?
17. Which of the following is a non-renewable resource?
18. What is afforestation?
19. Which organism is both producer and consumer?
20. What is global warming?
