1. Water is essential for

2. There are ...............major habitats.

3. The lightest part of atom is

4. By addition of what food becomes soft and fine

5. The reverse process of peristalsis is called

6. In which waves particles of medium move perpendicularly

7. What is the unit of frequency

8. Where are pollen grains located in

9. The rate of flow of charge is called

10. Blood is carried from lungs to heart by

11. Sound can not pass through

12. What is the name of our Galaxy

13. The largest artery is

14. flowers are .................part of plant

15. Food for algae is

16. which of the following is not used in human respiratory system

17. What is the mode of  transferring of heat for energy of sun reaching  us

18. Bile is released by

19. Human heart has ...............chambers

20. Which circuit is used in domestic wiring