DENDROLOGY

Detailed explanation-1: -Dolphins are mammals. They also have lungs, meaning they need to come to the surface to breathe using their blowhole. Sharks on the other hand, are cartilaginous fishes of the class Chondrichthyes, meaning their skeletons are made of cartilage rather than bone.

Detailed explanation-2: -Although dolphins swim in water and appear to be “fish-like” compared to other animals living in the ocean, they are classified as cetaceans (marine mammals) and not fish.