A sequence is given that describes the flow of water through different natural water bodies: Glacier, Waterfall, River, ?. Choose the most appropriate geographical feature from the options that usually comes next in this flow sequence.

Introduction / Context:
This question tests basic understanding of a typical natural water flow sequence on the Earth surface. It starts with a glacier, passes through a waterfall and a river, and asks you to identify the next stage. Such questions help you connect physical geography concepts about how water moves from high mountains to the oceans.

Given Data / Assumptions:

• Given sequence: Glacier, Waterfall, River, ?
• All options are geographical or water related terms.
• We assume a standard idealised flow from higher altitude to lower altitude and finally to the sea.

Concept / Approach:
In mountainous regions, snow accumulates and compacts to form glaciers. As glaciers melt, they feed streams that can form waterfalls. These streams combine into rivers. Eventually, rivers typically flow into seas or oceans. In many textbook diagrams of the hydrological cycle and river profiles, the final destination of river water is represented by a sea or ocean.

Step-by-Step Solution:
Step 1: Glacier is a large mass of ice found on mountains or near poles. When it melts, meltwater flows down due to gravity. Step 2: Meltwater from glaciers often forms streams that drop steeply over rock faces, creating waterfalls at high gradients. Step 3: These streams eventually join together to form rivers flowing through valleys and plains. Step 4: At the lower course of a river, it generally empties into a larger body of water such as a sea or ocean, depositing sediments at its mouth. Step 5: Therefore, the most logical next stage after Glacier, Waterfall, and River is Sea, representing the end point of the river flow in this simplified sequence.

Verification / Alternative check:
This sequence can be cross checked against the basic teaching in geography where mountain glaciers feed rivers and these rivers finally reach seas or oceans. Many diagrams show exactly this journey from ice in mountains to salt water bodies, confirming that Sea is the correct answer.

Why Other Options Are Wrong:
Rivulet is a small stream and would usually appear before or as part of the formation of a river, not after a river in a general flow sequence. Mountain is the place where glaciers form, so it would come at the beginning or before the glacier, not after a river. Ice is a solid state of water and links conceptually with glacier, again more likely at the start of the sequence. Pond is a small water body that may or may not be directly part of a major river flow sequence, and it is not the typical final destination of a large river system.

Common Pitfalls:
Students sometimes confuse smaller features like rivulets or ponds with large scale structures like rivers and seas. Another error is to think in terms of individual examples rather than the generalised textbook sequence. Remembering the broad path of water from glacial origins to the sea makes the logic straightforward.

Final Answer:
The natural next stage after Glacier, Waterfall, and River in this sequence is the Sea.