The world's largest _____ A23A splinters into smaller pieces.

The correct answer is iceberg. An iceberg is a large mass of freshwater ice that has broken off from a glacier or ice shelf and floats in the ocean. Icebergs can be quite massive, and as they drift and are affected by the surrounding water and temperature, they may break apart into smaller fragments. This phenomenon, known as calving, occurs when the structural integrity of the iceberg decreases due to melting or collisions with other objects, leading to the larger chunks splintering into smaller pieces.

In contrast, mountains, while they can erode and break down over time, do not 'splinter' in the same way that icebergs do. Volcanoes can erupt and produce lava and ash, but they do not typically splinter into smaller pieces; rather, they may collapse or create new landforms. Deserts are defined regions with very little precipitation and are not formed by large masses that would splinter. Thus, icebergs are the only option that accurately reflects the context of breaking into smaller pieces.