• # question_answer If BOD of a river is high, it means that the river A)  Is not polluted B)  Is very polluted C)  Does not have green plants D)  Get least amount of light

[b] Biochemical oxygen demand (BOD) is the amount of dissolved oxygen needed (i.e., demanded) by aerobic biological organisms to break down organic material present in a given water sample at certain temperature over a specific time period. The BOD value is most commonly expressed in milligrams of oxygen consumed per litre of sample during 5 days of incubation at $20{}^\circ C$ and is often used as a surrogate of the degree of organic pollution of water.