Which of the following options will replace the question mark (?)?
Earthworm : Annelida :: Starfish : ?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → Echinodermata
The pair links an animal with the phylum (major animal group) it belongs to. The earthworm has a body made of many ring-like segments, so it belongs to the phylum Annelida. The starfish is a spiny-skinned sea animal, so it belongs to the phylum Echinodermata.
Why the other options are incorrect
Option (1) Arms — Incorrect. These are body parts of a starfish, not the group it belongs to.
Option (2) Ocean — Incorrect. The ocean is where a starfish lives, not its animal group.
Option (4) Order — Incorrect. Order is the name of a level of classification, not the name of a particular group like Annelida.