Write the main characteristics of chondrichthyes

(a) Chondrichthyes are exclusively marine fishes.
(b) They have cartilaginous endoskeleton. Their body is streamlined.
© Mouth is located on ventral side.
(d) Gill slits are separate and without gill cover (operculum).
(e) Pelvic fins bear claspers in males.
(f) Skin is tough. It has minute placoid scales.
(g) Animals are predatory. They have powerful jaws with teeth e.g., sharks, rays, skates etc.