Final answer:
Glaciers are formed from snow that accumulates on land and changes into ice through compaction and metamorphism over time, even if the air temperature is above 0°C.
Step-by-step explanation:
The subject of this question is glaciers, which form as a result of snow that accumulates and transforms through compaction and snow metamorphism into ice. This process typically happens over many years and leads to the creation of dense, structured ice masses that can reshape landscapes through their slow movement.
Snow is the solid phase of water and is formed from ice crystals. The transformation from snow to ice requires a significant amount of heat for phase changes, making it a slow process. Despite air temperatures being above 0°C, snow can remain on mountain slopes due to the time necessary for this heat to transfer.