Q43 / 200 · NEET 2023 (All India) · Botany

Which one of the following statements is NOT correct?

  • A
    The amount of some toxic substances of industrial waste water increases in the organisms at successive trophic levels.
  • B
    The micro-organisms involved in biodegradation of organic matter in a sewage polluted water body consume a lot of oxygen causing the death of aquatic organisms.
  • Correct answer
    C
    Algal blooms caused by excess of organic matter in water improve water quality and promote fisheries.
  • D
    Water hyacinth grows abundantly in eutrophic water bodies and leads to an imbalance in the ecosystem dynamics of the water body.

Solution

During eutrophication of a water-body, there is continuous addition of sewage, organic waste which increases the BOD and subsequently decreases the DO. The addition of inorganic nutrients, like phosphate, causes extensive growth of algae, called algal bloom. This depleted the water quality and kills fish.

Hence, the correct answer is option: 'C'.

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