Final answer:
The diary entry supports the idea that the explorers had a hard and challenging life on nature's frontier.
Step-by-step explanation:
The diary entry best supports the idea that the explorers had a hard and challenging life on nature's frontier. The passage describes their difficult living conditions, such as not washing themselves or changing clothes and sleeping on the bare snow. It also highlights the physical exertion and minimal food they endured. These details emphasize the harshness of their expedition and demonstrate the challenges they faced while exploring.