Q. Which of the following is absent in polluted water?
A) Hydrilla
B) Water hyacinth
C) Larva of stone fly
D) Blue-green algae
Explanation
Stone files are exopterygote insects with aquatic nymphs, long antennae, biting mouth parts and weak flight. Adults have the tendency to feed on lichens and unicellular algae. Hence, these are absent in polluted water.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.