What is the primary difference between scree and talus?

Scree and talus are both terms related to geological formations found on slopes, but they denote different characteristics of these accumulations. The primary difference influencing the correct choice lies in their respective composition and how they behave underfoot.

Scree refers to a collection of small, loose rocks and gravel that are typically found on steep slopes or near cliff edges. Because of their size and the loose nature of the material, scree can create a surface that is more challenging to ascend due to the instability of the rocks, which can roll or slide underfoot. However, scree can often be easier to descend compared to talus because the smaller, lighter stones tend to provide better traction for descending, and the surfaces can facilitate controlled movement.

Talus, on the other hand, refers to larger rock fragments or boulders that have fallen from a cliff or steep slope. While talus can create a somewhat stable surface, the larger size of the rocks may make descending more precarious, as there is a higher chance of losing footing on the uneven and larger rocks.

Thus, the correct answer is that scree is generally easier to descend than talus due to its smaller size and looser composition, allowing for more manageable navigation when moving downhill.