Question

Which one of the following statement is not true ?

• A. Oxide of sulphur, nitrogen and carbon are the most widespread air pollutant
• B. pH of drinking water should be between 5.5 - 9.5
• C. Concentration of DO above 6 ppm is good for the growth of fish.
• D. Clean water would have a BOD value of less than 5ppm

Answer 1

The Correct Option is C

The correct option is(C):Concentration of DO above 6 ppm is good for the growth of fish.

DO stands for Dissolved Oxygen, which is a critical factor for aquatic organisms, including fish. Fish need oxygen to survive and thrive, just like any other living organism. Oxygen is dissolved in water, and the concentration of dissolved oxygen (DO) in the water directly affects fish health.

Fish need oxygen to carry out their metabolic processes, including respiration. Oxygen is exchanged between water and the fish's gills. If the concentration of dissolved oxygen in the water is too low, fish may suffocate, leading to stress, reduced growth, and even mortality. Fish that are subjected to water with DO concentrations below 6 ppm can experience a variety of negative effects, including impaired growth, reduced reproduction, and weakened immune systems.

Higher levels of dissolved oxygen, above 6 ppm, are generally considered beneficial for fish growth. They allow fish to respire efficiently, support their energy needs, and maintain their overall health. Adequate levels of dissolved oxygen also contribute to a healthy aquatic ecosystem by supporting other organisms such as aquatic insects, plankton, and other aquatic life forms that are part of the fish's food chain.

so, the correct statement is that a concentration of DO above 6 ppm is good for the growth of fish due to its critical role in their respiration and overall health.