A pond naturally contains water. In the same relationship of natural content, a mountain is primarily made up of which of the following?

Introduction / Context:
This analogy question tests basic understanding of natural features and what they contain or are composed of. The pair Pond : Water shows that a pond is a natural water body, and water is its essential content. The second pair Mountain : ? asks you to identify what forms the essential physical substance of a mountain. This is a simple science and environment based analogy that checks common knowledge rather than advanced geography.

Given Data / Assumptions:

A pond is a body of water, often shallow and relatively small.
Water is the main content that defines a pond as a water body.
A mountain is a large elevated feature of the earth's surface.
Options for the second term are Birds, Rocks, Animals and Climb.
We assume that the analogy focuses on the basic physical composition of each natural feature.

Concept / Approach:
The relationship in the first pair is between a natural feature and the material that chiefly constitutes or fills it. Without water, a pond would not be a pond. For mountains, the core material is rock. Although birds and animals may live on mountains and people may climb them, these are not the substances that physically make up a mountain. The mountain itself is largely composed of rocks and sometimes ice or soil on the surface, but rocks are the fundamental structural material. Therefore, Mountain : Rocks is the correct parallel to Pond : Water.

Step-by-Step Solution:
Step 1: Clarify the relationship in the first pair. A pond is a natural feature whose defining content is water. Step 2: Formulate the pattern: “natural feature : substance that primarily composes or fills it”. Step 3: Consider the nature of a mountain. It is a large mass that rises above the surrounding land. Step 4: Ask what material a mountain is primarily made of. The answer is rock, often with soil and vegetation on top. Step 5: Review the options. Birds and animals are living beings that may inhabit the mountain, not its base material. Climb is a verb describing an action. Step 6: Only Rocks matches the idea of basic physical composition in the same way that water does for a pond.

Verification / Alternative check:
To verify, try building similar analogies: Lake : Water, River : Water, Glacier : Ice, Desert : Sand, Hill : Rocks. Each pair matches a natural feature with its main substance. Mountain : Rocks fits smoothly into this pattern. If we attempted Mountain : Birds or Mountain : Animals, the structure would shift from material content to something like “habitat : inhabitant”, which is a different relationship type from Pond : Water. Climb is obviously a human activity, not material content. Thus, the pairing with rocks is strongly supported.

Why Other Options Are Wrong:
Birds and Animals are both possible inhabitants of a mountain environment, but they are not the defining material that forms the mountain itself. The physical body of the mountain would exist even in their absence. Climb is an action that people perform on a mountain, not a substance or content. None of these alternatives mirror the clear material relation that water has to a pond.

Common Pitfalls:
Some candidates get distracted by thinking about typical scenes rather than structures, and may loosely associate mountains with birds or animals because those creatures are commonly seen there. Others may look at Climb because mountains are objects that people climb. However, analogy questions require matching not just association but the same type of logical relationship. Keeping focus on physical composition rather than usage or inhabitants helps avoid such errors.

Final Answer:
Just as a pond is defined by containing water, a mountain is primarily composed of rocks, so Rocks is the correct answer.