Can you classify the following creatures according to what you have learned? Please try to answer the following questions: ① shrimp, ② turtle, ③ squid, ④ mussel, Σ jellyfish, Σ whale and Σ shark.

① Shrimp is segmented, with exoskeleton and appendages, belonging to arthropods;

(2) Soft-shelled turtle breathes with lungs, and its body temperature is unstable, so it belongs to reptiles;

(3) Squid and mussel belong to mollusks, which have a soft body and a mantle;

⑤ There are two layers of germ layers on the wall of aquatic mother body, and there is a digestive cavity in the body, with a mouth and no anus, which belongs to coelenterates;

⑥ Whale viviparous lactation belongs to mammals;

Sharks have scales, breathe with gills and swim with fins. They belong to fish.

(1) belongs to the mollusk is ③ squid? (4) mussels.

(2) Fish belongs to sharks.

(3) belongs to the arthropod is ① shrimp.

(4) The body structure of the above animals adapts to the underwater environment.

So the answer is:

( 1)③、④;

(2)⑦;

(3)①;

(4) in the water.