AP BIOLOGY

Detailed explanation-1: -Like every mammal, dolphins are warm blooded. Unlike fish, who breathe through gills, dolphins breathe air using lungs. Dolphins must make frequent trips to the surface of the water to catch a breath.

Detailed explanation-2: -Dolphins are part of the mammalian order Cetacea, which contains about 90 species of whales, dolphins and porpoises. Of these, the gigantic blue whale is the largest and the freshwater or river dolphin the smallest.

Detailed explanation-3: -Dolphins, whales, seals, sea lions, and otters are all mammals. They give birth to live young and nurse their young with milk.

Detailed explanation-4: -Dolphins, and other mammals, are warm blooded, give birth to live young, nurse their young, are born with hair, and breathe air. Sharks, like other fish, have gills to remove oxygen from the environment, are cold blooded, and have scales.

Detailed explanation-5: -Dolphins cannot breathe in water using gills as fish can, do not have scales, and are not cold-blooded. Dolphins are mammals that returned to the sea millions of years ago. Being a mammal means that: they breathe air (and do not have gills like fish);