11. Damaged seeds would ________ on top of water.

12. Cholera is  caused by_________.

13. Like synthetic fibre , plastic is also a  _______.

14. Metals react wih acids to produce  ________ gas.

15. The Fire produced by oil cannot be controlled by_______.

16. Migratory birds fly to far away places because of      _________ changes.

17. cell without well organised nucleus  are called  ________ cells.

18. Time period of a pendulum depends on its ________.  

19. The size of pupil becomes _________ when you see in dim light.

20. Shrillness of a sound  is determined by the  _________ of vibrationple


please I mark you brainlest ​