Chondrichthyes and Osteichthyes

Select the corect combinations is respect of characterstics of cartilaginous and bony fishes . {:("Character","Chondrichthyes","Osteichthyes"),((i)"Habitat","Freshwater","Marine"),((ii)"Scales","Placoid scales","Cyloid/Ctenoid"), ((iii)"Mouth","Suking mouth","Ventral mouth"),((iv)"Gills","4 pairs","5-7 pairs"):}

Select the correct option in respect of characteristics of each group. {:("Cyclostomes","Chondrichthyes","Osteichthyes"),((i)"Suking mouth","Ventral mouth","Terminal mouth "),((ii)"Scales absent","Placoid scales","Cycloid/Ctenoid scales"),((iii)"Marine","Marine","Marine adn freshwater"),((iv)6-15"pairs of gills",5-7 "pairs of gills without operculum",4 "pairs of gills with operculum"):}

Scales in Osteichthyes are

Read the following matches about chordates and it's characteristics. I. Petromyzon - belongs to cyclostomata and are endoparasites on some fishes. II. Scoliodon - a Chondrichthyes in which teeth are modified placoid scales. III. Hippocampus - a cartilaginous aquarium fish known as a sea horse. IV. lchthyophis is a limbless viviparous amphibian with direct development. Select the incorrect statements ?

Chondrichthyes is characterised by

Chondrichthyes can be differentiated from osteichthydes externally by

Assertion: Osteichthyes fishes swim constantly to avoid sinking . Reason: Air bladder is absent in fishes of Class Osteichthyes.

Members of Chondrichthyes have to swim continuously , because they

In chondrichthyes endoskeleton is made up of which tissue?

Statement(S). Fishes belonging to chondrichthyes have heterocercal caudal fin Reason(R). These fishes have an air bladder that acts as hydrostatic organ