役割

1. Origins, structure, and basic meaning

• Structure: 役割 (やくわり) is a function or responsibility performed by a person, thing, or environment.
• Basic usage: A moderator carries responsibility for guiding discussion; a forest supports the lives of many organisms.

2. Common pitfalls and similar expressions

• Assigned responsibility of a person and ecological function of an environment
  • 役割を担う presents responsibility carried by the moderator, while 役割を果たす presents a function the forest performs. The latter needs no deliberate assignment.