1. Sound can not travel in vacuum because

2. What are tissues

3. What is called universal solvent

4. The living things which eat meat are called

5. The power house of cell is called

6. which statement is true

7. The percentage of nitrogen in the air is

8. Which of them is energy of the sun

9. A machine makes the work

10. Which of them is best solvent

11. What is the speed of sound in air

12. Which of them is the most important machine

13. The living things which eat Grass are called

14. A solution consisting of two substance is called

15. Which organisms are called producers

16. Which gas is used in photosynthesis

17. Animals cells can not prepare their food because

18. Planet and their moons are the examples of

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

20. The main components of environment are called