Correct Answer: Nitrogen and phosphorus

Solution : The correct answer is (a) Nitrogen and phosphorus

Eutrophication is a process that occurs in bodies of water, such as lakes, rivers, and coastal areas, where there is an excessive accumulation of nutrients, particularly nitrogen and phosphorus. These nutrients can come from various sources, including agricultural runoff, wastewater discharge, and the use of fertilizers.

When an excess of nitrogen and phosphorus enters a body of water, it stimulates the growth of algae and other aquatic plants in an uncontrolled manner. This excessive growth of algae is known as an algal bloom. As the algae die and decompose, bacteria and other microorganisms consume oxygen, leading to oxygen depletion in the water. This depletion of oxygen can harm aquatic organisms, resulting in fish kills and a decline in biodiversity.

Eutrophication is a significant environmental issue and can lead to water quality degradation, ecological imbalances, and the disruption of aquatic ecosystems. Efforts to mitigate eutrophication include implementing nutrient management strategies, improving wastewater treatment, and promoting sustainable agricultural practices to reduce nutrient runoff.