Question

Assertion [A]: Eutrophication shows an increase in productivity of water.
Reason [R]: With increasing eutrophication, the diversity of phytoplankton increases.

• A. Both assertion and reason are true and the reason is the correct explanation for assertion.
• B. Both reason and assertion are true but the reason is not the correct explanation of the assertion.
• C. Assertion is true but the reason is false.
• D. Both the reason and assertion are false.

Answer 1

The correct option is B Both reason and assertion are true but the reason is not the correct explanation of the assertion.

Eutrophication is the enrichment of an ecosystem with chemical nutrients, typically compounds containing nitrogen, phosphorus, or both. It is a natural state in many lakes and ponds which have rich supply of nutrients. Eutrophication becomes excessive however, when abnormally high amounts of nutrients from sewage, fertilisers, animal waste and detergent enter streams and lakes causing excessive growth or bloom of microorganisms. With increasing eutrophication, the diversity of the phytoplankton community of a lake increases and the lake finally becomes dominated by bluegreen algae.