(三)Dolphins are different from fish in many ways. Dolphins must come up to the surface to breathe. Fish can breathe under water. Dolphins have one blowhole. They breathe in and out through it. Fish do not have blowholes. Dolphins have smooth skin. A fish’s skin is not smooth. Dolphins are mammals. A mother dolphin nurses her calf. Fish are not mammals. Dolphins “see” objects by making sounds and listening for an echo. This is called echolocation. Fish can not do this. Dolphins are very smart. Some learn to do tricks. Fish don’t appear to be as smart. Now, you know why dolphins are not fish.
6.( ) Are dolphins fish?
(A)Yes
(B) No
(C) We don’t know.
(D)We have no idea