Which of the following landforms is created by living organisms?

Coral reefs are structures formed primarily by living organisms, particularly corals. These marine animals secrete calcium carbonate, which accumulates over time to build large, complex structures that provide habitat for a wide variety of marine life. The process is a collaborative effort among various organisms, including corals, algae, and sponges, contributing to the biodiversity found within these ecosystems.

In contrast, mountain ranges are typically formed through geological processes such as tectonic plate movements, volcanic activity, or erosion, and are not the direct result of biological activity. Volcanic islands arise from volcanic eruptions and the accumulation of lava, while deserts are shaped by climatic conditions and erosion rather than by living organisms. Therefore, coral reefs stand out as the landform created by the activities of living organisms.