Odd one out — Arthropod classes: UPSC Prelims PYQ 2014
Among the following organisms, which one does not belong to the class of other three?
- Crab
- Mite
- Scorpion
- Spider
Explanation
Option (a) is the correct answer
- Crab: Crabs belong to the class Crustacea, which is a subgroup of the phylum Arthropoda. Crustaceans are characterized by having a hard exoskeleton, two pairs of antennae, and gills for respiration.
- Mite, Scorpion, and Spider: These organisms belong to the class Arachnida, which is also a subgroup of the phylum Arthropoda. Arachnids are characterized by:
- Having four pairs of legs (eight legs).
- Absence of antennae.
- Bodies divided into two main segments: cephalothorax and abdomen.
Answer: (a) Crab; Difficulty Level: Medium
