Marine animals with streamlined body and having cartilaginous endoskeleton belongs to which class of the superclass Pisces ?

AOsteichthyes

BCephalaspidomorphi

CMyxini

DChondrichthyes

Answer:

Super class Pisces:

Class – Chondrichthyes:

They are marine animals with streamlined body and have cartilaginous endoskeleton.
Mouth is located ventrally.
Notochord is persistent throughout life.
The skin is tough, containing minute placoid scales.
Teeth are modified placoid scales which are backwardly directed.
Their jaws are very powerful. These animals are predaceous.
Due to the absence of air bladder to swim constantly to avoid sinking
Heart is two-chambered ( one auricle and one ventricle).
Some of them have electric organs (e.g., Torpedo) and some possess poison sting (e.g., Trygon).
They are cold blooded (poikilothermous) animals, i.e., they lack the capacity to regulate their body temperature.
Sexes are separate.
In males pelvic fins bear internal fertilisation and many of them are viviparous.

Examples:

Challenger App