Classification – Animal classes/habitats: three are mammals; one is an insect. Identify the odd one out. Options: Langur, Whale, Scarab, Donkey.

Introduction / Context:
Biological classification can separate options by class. Mammals share key traits distinct from insects, making the outlier easy to spot.

Given Data / Assumptions:

• Langur: primate (mammal).
• Whale: marine mammal.
• Donkey: equid (mammal).
• Scarab: beetle (insect).

Concept / Approach:
Group by biological class: Mammalia versus Insecta.

Step-by-Step Solution:
Identify Langur/Whale/Donkey as mammals.Identify Scarab as an insect.Therefore, Scarab is the odd one out.

Verification / Alternative check:
Taxonomic references confirm whales, langurs, and donkeys are mammals; scarabs are coleopteran insects.

Why Other Options Are Wrong:
Langur/Whale/Donkey: All belong to class Mammalia.

Common Pitfalls:
Assuming “whale” is a fish due to habitat; it is a mammal.

Final Answer:
Scarab