Step-by-step explanation:
A dolphin is not a fish but is a mammal. Dolphins share many similarities with fish, including living in water and having streamlined bodies that help them swim efficiently. However, dolphins are warm-blooded and breathe air through lungs, unlike fish which are cold-blooded and breathe through gills. Additionally, dolphins nurse their young with milk and have hair on their bodies, which are both characteristics of mammals. Therefore, even though dolphins may appear similar to fish, they are a distinct type of animal with unique characteristics and traits that classify them as mammals rather than fish.