SSC CGL 2024 Tier-I · 17 September 2024, Shift 2 · General Awareness · Question 25 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 6 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 does NOT belong to the category of Porifera?

(a)Spongilla
(b)Hydra
(c)Euplectella
(d)Sycon

Answer

Why

Correct — B. Hydra is a cnidarian, not a sponge — option (b).

Porifera are the sponges: no true tissues, no mouth, no nervous system. Water is drawn in through pores called ostia, driven through by collar cells, and leaves by a single large opening, the osculum. Spongilla, Euplectella and Sycon all fit that description.

Hydra has a mouth ringed by tentacles carrying stinging cells, and belongs to Cnidaria, which reaches the tissue level of organisation.

Why the others are wrong

(a)
Spongilla — Spongilla is the common freshwater sponge. Freshwater habitat is the only unusual thing about it, and it is a poriferan like the others.
(c)
Euplectella — Euplectella, Venus's flower basket, is a glass sponge with a skeleton of silica spicules. Still Porifera.
(d)
Sycon — Sycon, also written Scypha, is the standard laboratory sponge used to demonstrate the water canal system. Porifera again.

Concept

Porifera sit at the cellular level of organisation — a body of loosely coordinated cells with no true tissues, no organs and no nervous system.

They feed through a water canal system. Water enters by ostia, is driven along by the beating flagella of choanocytes, or collar cells, and exits by the osculum. The skeleton is built of spicules of calcium carbonate or silica, or of spongin fibres.

Cnidaria, the next phylum up, reaches the tissue level, is radially symmetrical, and carries stinging cells called cnidoblasts. Hydra belongs there.

This is a NOT item, so the work is to spot the one animal from a different phylum rather than to define sponges from scratch.

Key facts

Porifera are the sponges and show the cellular level of organisation, without true tissues.
Water in a sponge enters through ostia and leaves through the osculum, driven by choanocytes.
Spongilla, Euplectella and Sycon are all members of Porifera.
Hydra belongs to Cnidaria, has tentacles bearing cnidoblasts, and shows the tissue level of organisation.

Study next

Levels of organisation across the animal phyla, from cellular to organ-systemCharacteristic examples of Porifera, Cnidaria, Platyhelminthes and ArthropodaSymmetry in animals, covering asymmetrical, radial and bilateral forms

Common traps

Guessing out Spongilla or Sycon because the names are unfamiliar. Both are Porifera.
Treating Hydra as a sponge because it is small, aquatic and usually attached in one place.

Phylum-and-example matching comes as a single odd-one-out or a single example. Arthropoda is asked the same way at 19 Sep 2024, 09:00, GA Q.6.

Related PYQs

No directly related past PYQ was found.