NDA (I) 2022 GAT Q75: Which one of the following belongs to

Q: What is the answer to NDA (I) 2022 GAT Q75?

A. Correct — A, Dogfish. Pisces is the group of true fishes. The dogfish is a small shark — a cartilaginous fish — so it genuinely belongs to Pisces. The other three names contain 'fish' but are not fishes at all.

NDA (I) 2022 General Ability Test · Question 75 of 150

Question text verified against the official NDA question paper.

Which one of the following belongs to 'Pisces'?

(a)Dogfish
(b)Jellyfish
(c)Silverfish
(d)Starfish

Answer

Why

Correct — A, Dogfish. Pisces is the group of true fishes. The dogfish is a small shark — a cartilaginous fish — so it genuinely belongs to Pisces. The other three names contain 'fish' but are not fishes at all.

Why the others are wrong

(b)Jellyfish — Despite its name, a jellyfish is not a fish; it is a cnidarian (phylum Cnidaria) with a soft, umbrella-shaped body and no backbone.
(c)Silverfish — The silverfish is a wingless insect (an arthropod), not a fish — it lives on land, among books and in cupboards.
(d)Starfish — The starfish (sea star) is an echinoderm (phylum Echinodermata), related to sea urchins, not a fish.

Concept

In classical classification, Pisces denotes the vertebrate fishes — aquatic, gilled, cold-blooded animals with fins. Many animals carry the word 'fish' in their common names without being fishes; among the options only the dogfish (a shark) is a true fish.

This is a name-versus-nature trap. Jellyfish, silverfish and starfish are all misleading common names drawn from three different phyla; the dogfish alone is a vertebrate fish belonging to Pisces.

Key facts

Pisces are cold-blooded aquatic vertebrates with gills and fins.
Dogfish is a small shark — a cartilaginous fish (class Chondrichthyes).
Jellyfish are cnidarians, starfish are echinoderms, and silverfish are insects.
Common names ending in 'fish' often belong to non-fish groups.

A spiny dogfish (Squalus acanthias), a small shark and a true fish, resting on the seabed — the dogfish is a true fish — a small shark belonging to Pisces — unlike the misleadingly named jellyfish, starfish or silverfishImage: Doug Costa, NOAA/SBNMS · Wikimedia Commons (Public domain)

Study next

Classification of the animal kingdom into phylaCharacteristics of the class Pisces (fishes)Cartilaginous fishes versus bony fishesMisleading common names in biology

Common traps

Being misled by the word 'fish' in jellyfish, starfish and silverfish.
Assuming a starfish or jellyfish is a vertebrate.

An odd-one-out on which 'fish' is actually a fish, testing basic animal classification.

Related PYQs

No directly related past PYQ was found.

Practice

practice — not a real PYQ
Which one of the following is not a true fish?
- (a)shark
- (b)catfish
- (c)jellyfish
- (d)eel
Answer(c) jellyfish — it is a cnidarian, not a fish.
practice — not a real PYQ
Starfish belongs to which phylum?
- (a)Chordata
- (b)Echinodermata
- (c)Cnidaria
- (d)Arthropoda
Answer(b) Echinodermata — starfish are echinoderms, not fishes.