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 S in water decreases too much due to which the fish living in the lake suffocate and die. What are P, Q R and S? Name this process

The farmers use large amounts of a substance P in the fields to increa

1.	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 S in water decreases too much due to which the fish living in the lake suffocate and die. What are P, Q R and S? Name this process
Answer» stance P is FERTILIZER. The fertilizers act as nutrients for the algae to grow. When these algae die, they act as a nutrient for decomposers like bacteria. As a result of this PROCESS, a LOT of oxygen in the WATER gets used up and LEADS to the deficiency of Oxygen in the water.