Same chapter3 marksDifficulty: Medium
What are biofertilisers and biocontrol agents? Give one example of each.
Microbes in Human Welfare
3 marksDifficulty: Medium
What is biochemical oxygen demand, and what does a high value indicate?
Original Khojo Papers practice question — not from a past board paper.
Answer
Biochemical oxygen demand is the amount of oxygen that would be consumed if all the organic matter in one litre of water were oxidised by bacteria. A high value indicates a large amount of organic matter, that is heavy pollution, and it means that little oxygen is left for aquatic life.
No citable source has been recorded for this record. Treat it as practice material, not as fact.
Explanation
It is used to measure how effectively sewage has been treated.
Related questions
From the same topic and chapter, at a similar level.
Same chapter3 marksDifficulty: Medium
How is biogas produced and what does it contain?
Microbes in Human Welfare
Same chapter3 marksDifficulty: Medium
Name three microbes used in industry and state the product obtained from each.
Microbes in Human Welfare
Same chapter3 marksDifficulty: Medium
Describe the role of microbes in sewage treatment.
Microbes in Human Welfare
Same subject3 marksDifficulty: Medium
Describe the structure and functions of the placenta.
Human Reproduction
Same subject3 marksDifficulty: Medium
Define apomixis and parthenocarpy, and state the practical use of each.
Sexual Reproduction in Flowering Plants