Which of the following is/are not the characteristics of the class Osteichthyes? (i) The body is streamlined and mouth is terminal. (ii) Gills are covered by an operculum. (iii) Skin covered with cycloid and placoid scales. (iv) Many of them are viviparous.
Osteichthyes are the group of bony fishes that are considered as the largest group of vertebrates. They include marine and freshwater fish that have a streamlines body and the mouth is terminal. They have skin covered with cycloid, ctenoid, or ganoid scales. They have four pairs of gills that are covered by an operculum on both sides. Most forms of these fishes are oviparous.
Thus, the correct answer is (B).
Match the following columns and select the correct option. Column - I Column - II (a) 6-15 pairs of gill slits (i) Trygon (b) Heterocercal caudal fin (ii) Cyclostomes (c) Air Bladder (iii) Chondrichthyes (d) Poison sting (iv) Osteichthyes
Which of the following is a correct match?
Which one of the following categories of animals, is correctly described with no single exception in it?
Pelvic claspers are found in
Hippocampus is called as 'sea horse', becuase