Choose the correct statement
- All mammals are viviparous.
- All cyclostomes do not possess jaws and paired fins.
- All reptiles have a three-chambered heart.
- All pisces have gills covered by an operculum.
Answer
(2) All cyclostomes do not possess jaws and paired fins.
Solution
As per NCERT, cyclostomes (e.g. Petromyzon, Myxine) have a sucking and circular mouth without jaws, and paired fins are absent.
∴ Statement (2) is correct.
∵ Monotremes such as platypus are oviparous, crocodiles have a four-chambered heart, and cartilaginous fishes (Chondrichthyes) have gill slits without an operculum,
⇒ statements (1), (3) and (4) are wrong.
Answer: (2)