Match the serial numbers of the group characteristics of the following animals. (1) SINONOVACULA constricta A. The body is radially symmetrical with stinging cells on its surface; Have a mouth and no anus (1) SINONOVACULA constricta belongs to mollusk, which is characterized by its soft body, outer mantle, hard shells and feet with various shapes.

(2) Hydra belongs to coelenterates, which are characterized by living in water; The body is radially symmetrical; There are stinging cells on the body surface, mouth without anus; The body wall is composed of endoderm, ectoderm and mesoderm. There is a digestive cavity in the body.

(3) Leeches belong to annelids, which are characterized by a cylindrical body, consisting of many similar annular segments, assisted by bristles and warty feet.

(4) Ascaris is a linear animal, which is characterized by a slender, cylindrical body, a cuticle on its surface, a mouth, an anus and a prosthetic cavity.

(5) The planarian belongs to a flat animal. The main characteristics of the flat animal are symmetrical on both sides of the body (left and right), flat back and abdomen, three germ layers on the body wall, no body cavity, and the circulatory system consisting of mouth, pharynx and intestine without anus.

(6) Grasshoppers belong to arthropods, and the characteristics of arthropods are: the body is composed of many segments and divided; The body surface has a tough exoskeleton, feet (appendages) and tentacles.

Therefore, the answer is: (1) d; （2）A； （3）C； （4）B； （5）F； （6）E．