Choose the correct statements.
(1) All mammals are viviparous
(2) All cyclostomes do not possess jaws and paired fins
(3) All reptiles have a three-chambered heart
(4) All Pisces have gills covered by an operculum
(2) Cyclostomata is a class belonging to section 1-Agnatha of subphylum Vertebrata. It is a paraphytelic superclass of jawless fishes. They lack paired fins too.
Thus, option (2) is correct.