SSC CGL 2024 Tier-I · 19 September 2024, Shift 1 · General Awareness · Question 6 of 100

Text as printed on a candidate's response sheet for this shift; answer per SSC's tentative key as marked on that sheet. Solution last reviewed 10 September 2026.

Where this paper and its answers come from

SSC does not publish CGL question papers or a public answer key. The questions and options here are reproduced as printed on a candidate's own response sheet for this shift — the Commission's text, unchanged. Each answer is SSC's tentative key as marked on that sheet; SSC allowed challenges to it and never publishes a final key. The solutions are written by UnlockIAS.

Which of the following is an example of Phylum Arthropoda?

(a)Pila
(b)Butterfly
(c)Nereis
(d)Hirudinaria

Answer

Why

Correct — B. A butterfly carries the three features that define Arthropoda: a chitinous exoskeleton, jointed appendages, and a body segmented into head, thorax and abdomen.

Butterflies sit in class Insecta — three pairs of legs, two pairs of wings, one pair of antennae.

One test settles the item. Ask which animal has jointed legs; the remaining three are a snail and two worms, and none of them does.

Why the others are wrong

(a)
Pila — Pila, the apple snail, is a mollusc. It has a soft unsegmented body, a muscular foot and a calcareous shell, and no jointed appendages at all.
(c)
Nereis — Nereis, the marine sandworm, belongs to Annelida. Its body is ringed into true segments and it bears lateral parapodia, but parapodia are fleshy flaps rather than jointed limbs.
(d)
Hirudinaria — Hirudinaria, the Indian cattle leech, is also an annelid. It moves by anterior and posterior suckers, which is a giveaway that it has no legs to joint.

Concept

Arthropoda is the largest phylum in the animal kingdom, and its name means jointed feet.

Alongside the exoskeleton and jointed appendages it has an open circulatory system, with blood filling a body cavity called the haemocoel rather than staying inside vessels.

Its familiar classes are Insecta (cockroach, butterfly), Crustacea (prawn, crab), Arachnida (spider, scorpion) and the myriapods (centipede, millipede).

The neighbouring phyla in an NCERT list are Mollusca, soft-bodied and usually shelled, and Annelida, segmented worms. Segmentation alone will not separate an annelid from an arthropod.

SSC gives the phylum and four genus names, so the work is recognising each genus, not reciting phylum characters.

Key facts

Arthropoda is the largest phylum in the animal kingdom.
Arthropods have a chitinous exoskeleton, jointed appendages and an open circulatory system.
Pila is a mollusc, while Nereis and Hirudinaria are annelids.
Butterflies belong to class Insecta, with three pairs of legs and two pairs of wings.

Study next

Body-plan tests that separate Annelida, Mollusca and ArthropodaThe classes within Arthropoda and one standard example of eachThe NCERT list of representative genera for every invertebrate phylum

Common traps

Sorting by habitat instead of body plan, which makes the aquatic Pila and marine Nereis look alike.
Treating segmentation as the arthropod test when annelids are segmented too.

SSC's animal-classification items name one phylum and four genera, so the reliable preparation is a memorised example per phylum rather than a list of characters.

Related PYQs

No directly related past PYQ was found.