BOD (Biochemical Oxygen Demand) is best defined as

Question

Accepted Answer

B. {'text': 'Oxygen consumed if all organic matter in 1 L is oxidised by bacteria', 'label': 'B'}

1. BOD measures the rate of oxygen uptake by micro-organisms in a water sample.
2. NCERT: BOD is the amount of O₂ that would be consumed if all the organic matter in one litre of water were oxidised by bacteria.
3. Higher BOD indicates more polluting organic load.
4. BOD is reduced during secondary (biological) sewage treatment.
_Source: NCERT Class 12 Biology, Ch 8 "Microbes in Human Welfare", §8.3_

Answer

{'text': 'The oxygen produced by algae in water bodies during photosynthesis', 'label': 'A'}

Answer

{'text': 'The oxygen dissolved at saturation level in pure fresh water sample', 'label': 'C'}

Answer

{'text': 'The oxygen used by aquatic fish in a river during regular respiration', 'label': 'D'}