Question

Sea Horse is a
(a) Coelenterate
(b) Bony fish
(c) Mammal
(d) Reptile

Answer 1

Hint: Seahorse is an animal with a unique property of role reversal, where the males take care of the eggs while they hatch. It belongs to a class of organisms that possess special organs to help them afloat and control their buoyancy.

Complete answer:
Bony fishes or Osteichthyes are the aquatic vertebrates who possess bony endoskeleton in the adult form. The endoskeleton is cartilaginous in the embryonic stage. They are ectothermic i.e. cold-blooded. Bony fishes occur in every kind of waters – freshwater, marine, brackish. Sea horse or Hippocampus is an example of marine bony fish.

Additional Information: The neck and head of the fish resemble horses while the tail is prehensile i.e it has the ability to grasp or hold any object. Its special characteristic is its sexual dimorphism where the male bears a brood pouch. Females lay their eggs in the brooch pouch. The eggs remain in the pouch till they hatch. This shows that parental care is exhibited by males. Also, the pelvic and caudal fins are absent in sea horses. They have a long snout and neck which aids in their feeding.
Coelenterates are aquatic and mostly marine radially symmetrical animals with a tissue level of organisation. Their characteristic feature includes the presence of cnidoblasts or stinging cells on their tentacles. They use it for defence and offence. E.g. Hydra, Obelia.
Reptiles are the chordates who are mostly terrestrial with creeping or crawling mode of locomotion. their body is covered by dry and cornified skin with the presence of scales or scutes. E.g. Snakes, Lizard.
Mammals are chordates distinguished by the presence of mammary or milk-producing glands and hair on their body. E.g. Humans, Blue whale.
So, the correct answer is ‘Bony fish.’

Note: -Marine bony fishes live in an environment of high concentration of salt and Their blood and tissue fluids are hypotonic to the surrounding medium.
-This poses a threat of water loss from the body of fishes into the environment by osmosis. In such circumstances, the marine bony fishes are adapted to take large amounts of water into the gut and reduce the production of urine. Also, excess of salt which has entered the body is excreted from the gills and kidneys.