Disability evaluations after injuries:
(a) Explain the following terms: "duration of disability" and "degree of disability".
(b) Explain how degrees of disability after injuries are assessed for the following conditions:
a. A unique injury for a worker who was well before the injury
b. Multiple injuries affecting the same organ or functional system
c. Injuries which are coexistent and do not have any functional correlation
d. A fresh injury sustained by a worker after a pre-existing incapacity