Describe a "fill slope."

A fill slope refers to the surface that is formed when soil or other materials are added to an area, which effectively raises its elevation. This process is known as "filling" and is commonly used in construction and earthworks to create a level surface or stabilize land. In engineering and surveying contexts, fill slopes can be critical for providing adequate drainage, supporting structures, and preventing erosion.

The concept of fill slopes is essential in construction projects, as they can affect both the stability of the newly created terrain and the surrounding environment. Builders and engineers must consider various factors, such as the type of soil used, the angle of the slope, and adequate compaction to ensure that the slope is stable and does not lead to issues like landslides or erosion in the future.

In contrast, the other options describe different processes or structures that do not align with the definition of a fill slope. Natural erosion relates to the removal of soil rather than the addition of material, concrete and asphalt slopes pertain to hard surfaces used in road construction, and retaining wall slopes relate to structures designed to hold back soil rather than filling it. Thus, the correct identification of a fill slope enriches one’s understanding of earthworks practices.