Final answer:
The geography of the route made movement difficult for the explorers due to the Rocky Mountains, challenging river navigation, and dense forests.
Step-by-step explanation:
The geography of the route followed by the Corps of Discovery made movement difficult for the explorers in several ways. One challenge was the presence of the Rocky Mountains, which required the explorers to find passable routes through rugged terrain. Another difficulty was navigating the Missouri River, which had strong currents and shifting sandbars. Additionally, the dense forests and thick vegetation in some areas made it hard to travel and gather food.
Learn more about challenges faced by the Corps of Discovery