1. The power house of cell is called

2. Sound can not travel in vacuum because

3. A machine makes the work

4. The percentage of nitrogen in the air is

5. What is called universal solvent

6. Planet and their moons are the examples of

7. A solution consisting of two substance is called

8. Which of them is the most important machine

9. The living things which eat Grass are called

10. Which of them is best solvent

11. Which organisms are called producers

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

13. Animals cells can not prepare their food because

14. The living things which eat meat are called

15. Which gas is used in photosynthesis

16. What is the speed of sound in air

17. What are tissues

18. which statement is true

19. The main components of environment are called

20. Which of them is energy of the sun