A group of students found a fish on the sea beach ad carried it to their teacher. The teacher told them that it is a bony fish and not a cartilage fish. Why a cartilage fish has to swim continuously to stay at a particular depth in water?

Which type of tail fin is found in cartilage fishes?

While studying pollution of water, a group of students observed mortality of fish in the river flowing through the city and also in the pond which was away from the city but was adjacent to the crop fields. They further found that drains of the city discharged sewage into the river and the water from farms flowed into the pond. Explain how these could be the cause of fish mortality.

Choose the correct alternative: Copulatory organs claspers are found in males of cartilage fishes/bony fihes/both cartilage and bony fishes.

The "clown fish" lives among the tentacles of sea anemone. What is this interaction between them called and why?

Tabulate four differences between cartilage and bony fishes.