CBSE Class 9 Answered

(a) Characteristic features of Protochordates:

(i) They are bag-like, sessile, soft-bodied, non-metameric animals.

(ii) Adult body is covered with a tunic or test containing cellulose.

(iii) Notochord is present only in the tail or free-living tadpole-like larva.

(iv) Dorsal tubular nerve cord is present in larval form and it degenerates in the form of small ganglion in the adult.

(b) (i) Frogs live both in water and land. It uses its skin to breathe in water and lungs to breathe on land.

(ii)Whale is warm blooded animal. It gives birth to young ones and has mammary glands so it is considered as a mammal.