1. Animals cells can not prepare their food because

2. Sound can not travel in vacuum because

3. Planet and their moons are the examples of

4. A solution consisting of two substance is called

5. The percentage of nitrogen in the air is

6. A machine makes the work

7. The living things which eat Grass are called

8. which statement is true

9. Which of them is the most important machine

10. What is called universal solvent

11. Which gas is used in photosynthesis

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

13. Which of them is best solvent

14. The living things which eat meat are called

15. What is the speed of sound in air

16. Which organisms are called producers

17. What are tissues

18. The main components of environment are called

19. Which of them is energy of the sun

20. The power house of cell is called