Final answer:
True, the angle of repose is the steepest angle at which loose fragments on a slope can rest without moving, and it varies with the type of material and moisture conditions.
Step-by-step explanation:
The statement that the steepest angle loose fragments on a slope can assume without downslope movement is the angle of repose is True. The angle of repose is defined as the maximum angle at which a soil, sediment, or other loose material can accumulate on a slope without moving downslope. This angle is crucial for understanding the stability of slopes and is a factor in the occurrence of landslides and other mass wasting events. Factors such as the type of sediments, moisture conditions, and external influences like earthquakes and volcanic eruptions which can over-steepen slopes, affect the angle of repose and therefore the stability of the slope.