Question

In shark the mouth and the nares are
A. Ventral and dorsal
B. Terminal and dorsal
C. Both ventral
D. Dorsal and Ventral

Answer 1

Hint: The sharks are the fishes that belong to the group of elasmobranch fish and they are distinguished by the cartilaginous skeleton, five-gill slits are on the side of the head. Modern shark is restricted within the clade. Shark breathes between the gills which are present at the back of the mouth.

Complete answer:
The shark belongs to the class Chondrichthyes. So the animals that belong to this group have a cartilaginous exoskeleton. The mouth is located on the ventral side and the notochord is resolved throughout their life. The gill slits are separate and without the operculum and the external nostrils or the nares are present on the ventral side of the head. The skin is tough which contains numerous minute placoid scales. The teeth are modified into placoid scales which are in the backward direction and their jaws are very powerful.
The speed and acceleration of the shark depend upon the shape of the tail as the tail gives thrust. The sharks have the heterocercal caudal fin in which the dorsal fin is generally larger than the ventral fin because the vertebral column of shark stretched into the dorsal parts which give a greater surface area for the attachment of muscles.
So, in sharks, both the mouth and the nares are located on the ventral side.

Note: The heart of the shark consists of a two-chambered one is the article and the other one is the ventricle. They are the cold-blooded animals and as a result, they cannot regulate their body temperature. They show internal fertilisation.