What is plucking in the context of glaciation?

Plucking, in the context of glaciation, refers to the process where a glacier, while moving, exerts pressure on the underlying bedrock, causing some of that rock to become dislodged and picked up by the ice. This occurs especially when the glacier encounters irregularities in the terrain, such as rocks or boulders. As the glacier advances, it can penetrate cracks and fissures in the rock, which can result in fragments being pulled away. This process contributes significantly to the landscape, as it shapes and sculpts the terrain by eroding the bedrock and creating features unique to glaciated areas.

The other options do not accurately describe plucking. Creating glacial landforms focuses more on the overall effects of glaciation rather than the specific mechanism of plucking. The breaking away of ice from a glacier pertains to calving or other forms of ice loss, which is separate from the interaction between ice and rock. Measuring glacier thickness involves different methods entirely, such as using radar or other instruments, rather than describing a geological process like plucking.