Q.90. BOD values of different samples of water are given.

Which of the above given sample will have number of Daphnia ?
(1) A
(2) B
(3) C
(4) D

Dear student,
The answer will be (3) C.
Daphnia is a freshwater species which is found in fresh water bodies like lakes,pond.The biochemical oxygen demand (BOD) of fresh water is less because it is less polluted or not polluted.Thus,more will be dissolved oxygen in fresh water as compared to polluted water and more Daphnia will be present in fresh water which has least BOD.
Regards