Final answer:
Leah is correct because both weathering and erosion involve the actions of wind, water, and ice, with glaciers being a significant erosive agent. Erosion differs from weathering in that it includes the transportation of materials, not just their breakdown, and glaciers are well-known for shaping landscapes.
Step-by-step explanation:
Between Leah and Justin's statements on weathering and erosion, Leah is correct. Both weathering and erosion involve the action of wind, water, and ice. Weathering is the process that breaks down rocks and other materials on Earth's surface. Erosion, on the other hand, refers to the transportation of these materials by natural forces, including ice in the form of glaciers, which play a significant role in carving landscapes and transporting debris.
Indeed, glaciers are key erosional agents. They scrape and pick up rock material as they move, fundamentally reshaping landscapes over time. This differentiates from weathering, where the breakdown occurs in situ, with no movement involved in the process.
Justin is also partly correct in stating that plants and animals contribute to erosion, but they are typically involved in biological weathering - plants grow into rocks and animals burrow, causing both to fragment rock material. This material can later be removed by erosional processes. However, claiming that erosion does not involve ice is inaccurate, as glaciers are a potent force of erosion.