Question

Discuss the origin,characteristics and classification of fish

Answer 1

Characteristics of fishes:
They are exclusively aquactic animals.
They have streamlined body covered with scales. It ends in a muscular tail which helps in movement.
Fins are present, but limbs are absent.
Respiration occurs through gills by taking oxygen dissolved in water.
They are cold-blooded and have two chambered heart.
Most of them lay eggs.
Fishes are known as Pisces.
Pisces are of two types, based on the nature of their skeleton, i.e. Chondrichthyes and Osteichthyes.