Question

The farmers use large amounts of a substance P in the fields to increase the crop yield. The excess of P dissolves in water and runs into a lake. The substance P causes rapid growth of tiny green water plants Q in the lake which cover the whole lake like a green sheet. When the plants Q die, the organisms called R decompose them by utilizing S dissolved in lake water. The amount of dissolved Sin water decreases too much due to which the fish living in lake suffocate and die. What are P, Q, R and S?

Answer 1

Answer:

1. Substance P is Fertilizer
2. Substance Q is Algae
3. Substance R is Bacteria
4. Substance S is Oxygen

Explanation:

hope it helped pls mark as brainliest

Answer 2

P = Fertilisers

Q = Algae

R = Bacteria

S = Oxygen

Explanation:

• The overgrowth of algae is called eutrophication.
• When the bacteria use most of the oxygen in water, it causes lack of oxygen.
• This reduces the neutralisation of the green house gases present in the water and carbon dioxide produced by the respiration of fish and bacteria.
• The steps to prevent eutrophication include improving performance of water filer or water purifier, reducing presence of phosphorus in fertilisers and detergents, slow release of water from fields and limiting the usage of water.
• The steps to increase the quality of water that are effect by eutrophication include treating hypolimnetic water and adding iron or aluminium salts or calcium carbonate.