Concept:Liming neutralises excess acidity in pond water and improves conditions for fish life.
Explanation:Pond water often becomes acidic from decaying organic matter.
This acidity can stress or kill fish.
Liming means adding agricultural lime to the pond.
Lime raises the water pH and makes it less acidic.
It also supplies calcium, which fish need for healthy growth.
Better water quality encourages natural fish food like plankton.
Thus, liming makes the water suitable for fish survival.
Answer:B. liming