Which statement accurately describes the movement of a flowing glacier?

A flowing glacier can either advance or retreat, which captures the dynamic nature of glaciers influenced by various climatic and environmental factors. Advancing occurs when a glacier accumulates more mass from snowfall than it loses through melting and calving. Conversely, retreat happens when melting exceeds accumulation, causing the glacier to lose mass. This movement is not solely dictated by temperature changes, but also by variations in precipitation, the glacier's slope, and the substrate beneath it. Both advancing and retreating movements are essential to understanding the lifecycle of a glacier and its impact on the surrounding landscape.

Other statements do not provide a complete picture of a glacier's behavior. A glacier does not solely advance due to melting, nor does it remain stationary since movement is a fundamental characteristic of flowing glaciers. Additionally, while pressure can influence glacial movement, it is not limited to retreating scenarios. Thus, the understanding that a glacier can exhibit both advancing and retreating behaviors underlines the correct statement's accuracy.