Question

Choose the correct statement.

(a) All mammals are viviparous.

(b) All cyclostomes do not possess jaws and paired fins.

(c) All reptiles have a three­chambered heart.

(d) All pisces have gills covered by an operculum.

Answer 1

Ans: (b) All cyclostomes do not possess jaws and paired fins.

Sol: Ornithorhynchus and Tachyglossus are oviparous mammals. Crocodile is a reptile which possesses four chambered heart. In cartilaginous fish (except Chimaera) gills are not covered by an oper­ culum.