Here's why:

* Formation: Drumlins are formed by the deposition of glacial till. As glaciers move, they pick up and carry sediment (rock, sand, gravel, etc.). This sediment is then deposited in elongated, streamlined mounds as the glacier melts and retreats.

* Shape: The characteristic shape of a drumlin, with its steeper, blunt end facing the direction from which the glacier flowed, is directly related to the deposition of material by the glacier.

Therefore, drumlins are a direct result of glacial deposition and not erosion.