Final answer:
Darnall Army Community Hospital was the first of three military hospitals that played critical roles in different historical contexts, serving as centers for medical care and training during times of conflict and social change.
Step-by-step explanation:
Darnall Army Community Hospital was the first of three military hospitals to provide comprehensive care and medical training during significant historical events. In the accounts provided, hospitals played vital roles in various settings, acting as sanctuaries during wartime, offering care amidst harsh conditions, and advancing medical practice through training. Whether it was treating soldiers during World War I, providing care to refugees and freed individuals during the American Civil War, or establishing medical facilities in developing nations, hospitals have been crucial in both immediate medical intervention and the longer-term development of healthcare systems and administrations.