Final answer:
The statement about bones rolling down a hill and scavenging activity being area-dependent is true. Scavengers eat soft tissues of dead animals and their activity varies with an area's ecological characteristics, helping in the elimination of dead organisms.
Step-by-step explanation:
The statement "Bones can roll down hill. Scavenging activity is area-dependent." is a true statement. Scavengers are organisms that consume the soft tissues of dead animals, which could be the leftovers from a predator's kill. Their activity is often influenced by the ecological characteristics of an area, which can affect the presence and abundance of scavengers. Examples of scavengers include vultures, hyenas, and raccoons.
Regarding the scavenger being a decomposer, it is important to note that scavengers are not decomposers but they do play a similar role in that both help in the elimination of dead organisms. Decomposers like bacteria and fungi break down dead organic matter into simpler substances. On the other hand, scavengers typically consume larger pieces of dead animals.