Post-traumatic stress disorder is unique among psychological disorders because: a. the cause of the disorder may be specified with certainty b. the genetic markers for the disorder are well known c. the symptoms are generally mild and do not cause distress d. the risk factors are generally correlational

The answer is A. The cause of the disorder may be specified with certainty.

Post-traumatic stress disorder is a mental health condition that is triggered by a terrifying event which can arise from either experiencing or witnessing the event. Symptoms of this disorder may include flashbacks, nightmares and severe anxiety, as well as uncontrollable thoughts about the event.

Ithink it's a, but i might be wrong

Ongoing civil wars western roman empire finally collapsed476 c.e. romulus, the last of theroman  emperors in  the west, was overthrown by the germanic leader odoacer, who became the first barbarian to rule in rome. the order that the  roman empire  had brought towestern  europe for 1000 years was no more.