Final answer:
In glaciers, the zone of accumulation is where ice is gained, while the zone of ablation is where ice is lost. The correct answer to the question is C. accumulation, ablation.
Step-by-step explanation:
In glaciers, the zone of accumulation represents an area of net gain in ice, and the zone of ablation represents an area of net loss in ice. The correct answer is C. accumulation, ablation.
The zone of accumulation is where new snow and ice are added to the glacier, typically at higher elevations where the climate is colder and results in more snowfall than melting.
Conversely, the zone of ablation is where melting, sublimation, evaporation, or calving of ice exceeds the accumulation, commonly found at lower elevations or at the glacier's terminus. This dynamic between accumulation and ablation dictates whether a glacier grows or retreats over time.
For example, Glacier National Park in Montana has seen significant glacier retreat due to climate change, with the majority of its glaciers shrinking in size. The Grinnell Glacier, specifically, has lost a substantial portion of its mass in recent decades.