Which of the following characteristics is typically associated with landscapes shaped by glacial activity?

The correct answer is Presence of drumlins and morainic deposits.

Glacial activity leaves behind distinct erosional and depositional landforms due to the movement and melting of massive glaciers.
1. Drumlins: These are elongated, teardrop-shaped hills formed by the streamlined movement of glacial ice over till (glacial debris). The steep end points toward the direction from which the ice advanced, while the gentler slope points in the direction of ice movement.
2. Morainic Deposits (Moraines): These are accumulations of unsorted glacial debris (till) consisting of soil, rocks, and boulders deposited directly by a glacier as it advances or retreats.

Let's evaluate the other options:
- Growth of marine coral reef structures: Formed by biological activity of coral polyps in warm, shallow marine environments, unrelated to glacial activity.
- Deposition of river deltas at coastlines: Resulting from fluvial (river) processes where sediment is deposited at the mouth of a river.
- Accumulation of windblown sand dunes: Resulting from eolian (wind) deposition, typical of arid deserts or coastal beaches.

Therefore, drumlins and moraines are key landforms characteristic of landscapes shaped by glacial activity.