What geological features are caused by glacial erosion and melting?

U-shaped valleys and ribbon lakes are prime examples of the geological features formed as a result of glacial erosion and melting. When glaciers move, they carve out U-shaped valleys through a process called glacial plucking and abrasion. This massive ice movement sculpts the landscape, creating distinctive U-shaped profiles instead of the V-shaped valleys formed by river erosion.

As glaciers melt, they can leave behind depressions that fill with water, forming ribbon lakes. These lakes are characterized by their long, narrow shapes, often found within the valleys that were previously carved by the glaciers. The combination of erosion and subsequent melting of ice leads to the unique valley and lake formations associated with glacial landscapes.

The other geological features listed, such as cliffs and caves, plateaus and mesas, and dunes and deltas, result from different geological processes and are not primarily the products of glacial activity. Thus, the association of U-shaped valleys and ribbon lakes with glacial processes clearly makes them the correct answer in this context.