1. In which waves particles of medium move perpendicularly

2. What is the unit of frequency

3. Human heart has ...............chambers

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

5. Bile is released by

6. The largest artery is

7. There are ...............major habitats.

8. The lightest part of atom is

9. Where are pollen grains located in

10. The rate of flow of charge is called

11. The reverse process of peristalsis is called

12. Sound can not pass through

13. Which circuit is used in domestic wiring

14. By addition of what food becomes soft and fine

15. What is the name of our Galaxy

16. Water is essential for

17. flowers are .................part of plant

18. Food for algae is

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

20. Blood is carried from lungs to heart by