Question

Which of the following is not found in polluted water?

• A. Blue green algae
• B. Larvae of stone fly
• C. Water hyacinth
• D. Sewage fungi

Answer 1

The correct option is B Larvae of stone fly

Stoneflies are found in clean and cool flowing streams. They spend most part of their life in the larval form and are sensitive to water pollution. In particular, stoneflies are sensitive to changes in dissolved oxygen and water temperature. They need a high amount of dissolved oxygen to live comfortably. When the dissolved oxygen falls or the temperatures rise and stoneflies disappear. The presence of stoneflies is a reliable indicator of excellent water quality

So, the correct answer is 'Larvae of stone fly'