1. Animals cells can not prepare their food because

2. Which organisms are called producers

3. What is the speed of sound in air

4. The percentage of nitrogen in the air is

5. Sound can not travel in vacuum because

6. Planet and their moons are the examples of

7. Which of them is the most important machine

8. The living things which eat Grass are called

9. The power house of cell is called

10. What is called universal solvent

11. The main components of environment are called

12. The living things which eat meat are called

13. A machine makes the work

14. Which of them is energy of the sun

15. Which of them is best solvent

16. What are tissues

17. A solution consisting of two substance is called

18. which statement is true

19. Which gas is used in photosynthesis

20. The living things which eat both plants and meat are called