1. What is the speed of sound in air

2. What are tissues

3. A machine makes the work

4. which statement is true

5. Which organisms are called producers

6. Which of them is the most important machine

7. Which of them is best solvent

8. The living things which eat Grass are called

9. Which of them is energy of the sun

10. Animals cells can not prepare their food because

11. The percentage of nitrogen in the air is

12. Sound can not travel in vacuum because

13. Which gas is used in photosynthesis

14. What is called universal solvent

15. The main components of environment are called

16. A solution consisting of two substance is called

17. Planet and their moons are the examples of

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

19. The power house of cell is called

20. The living things which eat meat are called