Biochemical Oxygen Demand (BOD), is a measure of organic material present in water. BOD value less than 5 ppm indicates a water sample to be
1. Rich in dissolved oxygen
2. Poor in dissolved oxygen
3. Highly polluted
4. Not suitable for aquatic life
Given below are two statements:
Assertion (A): | If the BOD level of water in a reservoir is less than 5 ppm it is highly polluted. |
Reason (R): | High biological oxygen demand means the low activity of bacteria in water. |
1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
3. | (A) is true but (R) is false. |
4. | Both (A) and (R) are false. |