Whale is related to Mammal in the same way as Rat is related to which biological group?

Introduction / Context:
This analogy tests classification knowledge in biology. A whale is classified within a certain major group of animals, and a rat also belongs to a specific classification. Recognising these categories, and not being distracted by broader or unrelated groups, is key to answering correctly. Such questions are common in general science sections of competitive exams.

Given Data / Assumptions:

• Analogy: Whale : Mammal :: Rat : ?
• Options: Rodent, Mammal, Amphibian, Reptile.
• Whale is a large marine animal that breathes air and is scientifically classified as a mammal.
• Rat is a small animal commonly seen in households and fields with a specific order classification.
• Rodent is an order within the class Mammalia.

Concept / Approach:
In the analogy, the relationship between Whale and Mammal is that of animal to its class. All whales are mammals, even though they live in water. For the second pair, Rat must be linked to its more specific group, not simply to the whole class Mammal again. Rats are members of the order Rodentia, commonly called rodents. Therefore, the parallel relationship is Rat : Rodent, matching the pattern of individual example to classification group.

Step-by-Step Solution:
Step 1: Confirm the first pair. Whales give birth to live young, nurse them with milk, and breathe air through lungs. These features place whales in the class of mammals. Step 2: Identify the relationship as example animal to its classification group. Step 3: Consider the rat. A rat is clearly also a mammal, but the question expects a more specific group parallel to Mammal for whales. Step 4: Recall that rats belong to the order Rodentia, which includes mice, squirrels, and similar gnawing mammals. Commonly, such animals are referred to as rodents. Step 5: Match rat to rodent, just as whale is matched to mammal.

Verification / Alternative check:
Write out the completed analogy: Whale : Mammal :: Rat : Rodent. Whale is a kind of mammal. Rat is a kind of rodent. Although rats are also mammals, using mammal again would not parallel the more specific classification provided in the first pair, where mammal is the immediate group name for whales. In standard exam keys, rodent is regarded as the correct category for rats in this type of analogy.

Why Other Options Are Wrong:
Mammal: While true that a rat is a mammal, this answer is too broad, and it does not mirror the level of specificity intended by whale and mammal already used in the first pair. Amphibian: Amphibians are animals like frogs and salamanders that live part of their life in water and part on land, which does not match rats. Reptile: Reptiles include snakes, lizards, and crocodiles, and do not have the defining features of rats.

Common Pitfalls:
Many students quickly pick mammal because they know rats are mammals. However, they overlook that whales are already matched with mammal and that the second pair is expected to show a more specific group for rat. Others may be confused about which group rats belong to. Always remember that rats, mice, and squirrels are rodents, a distinct group within mammals.

Final Answer:
The correct completion of the analogy is Rodent, giving Whale : Mammal :: Rat : Rodent.