Question

Atoll is a geomorphic feature formed by

• A. glacial erosion
• B. wind flow abrasion
• C. fluvial deposition
• D. coral reef accumulation

Hint:

Atolls are ring-shaped coral reefs that form around submerged islands and grow into rings with a central lagoon.

Answer 1

The Correct Option is D

Step 1: Understanding an Atoll.
An atoll is a ring-shaped coral reef, island, or series of islets that encircle a lagoon. It forms through coral growth on submerged volcanic islands. The growth of coral reefs in shallow, tropical seas eventually creates these unique features.

Step 2: Analyzing the options.
(A) glacial erosion: This is incorrect, as atolls are not formed by glaciers but by coral reef accumulation.
(B) wind flow abrasion: Wind erosion can shape certain landforms but does not form atolls.
(C) fluvial deposition: This refers to river deposition, which is unrelated to the formation of coral reefs.
(D) coral reef accumulation: Correct — Atolls are formed by the accumulation of coral reefs around submerged islands.

Step 3: Conclusion.
The correct answer is (D) coral reef accumulation, as atolls form through the growth of coral reefs around a lagoon.