(3) The main characteristics of fish are that they live in water all their lives, breathe with their gills and swim with their fins, and most of them have scales. Crocodiles have scales. They breathe with their lungs and lay eggs. They are reptiles. Octopus and squid are mollusks with soft bodies and shells. Whales live in water, but breathe with their lungs, viviparous and have a constant body temperature, so they are mammals; Giant salamander, amphibian.

(2) It is not difficult to judge whether octopus and cuttlefish belong to mollusks and invertebrates, while goldfish, sharks, giant salamanders, crocodiles and whales belong to vertebrates. According to whether the body temperature is constant, they can be divided into: whales, warm-blooded animals; Octopus, cuttlefish, goldfish, shark, giant salamander, crocodile, warm-blooded animal.

So the answer is: (3) goldfish, sharks & yes; BSP&BSP (2) Is there a spine in the human body? Is Bsp temperature constant?