Final answer:
The word 'nevertheless' correctly fills in the blank, indicating that despite dangers, Jefferson and others had specific expectations of the West, including possible volcanoes and mammoths.
Step-by-step explanation:
Choose the answer that best completes the sentence below. Jefferson and other Americans expected that the West would be dangerous; nevertheless, they expected there to be volcanoes and mammoths.
The choice of the word 'nevertheless' provides a contrast to the initial expectation while continuing the thought that there were indeed dangers in the West that Americans anticipated.
The sentence implies that despite the known dangers there were still unforeseen natural phenomena like volcanoes and possibly mammoths as part of the broader landscape and wildlife of unexplored territories.
Historical exploration and expansion involved confronting both real and imagined dangers. Jefferson's vision for expansion included Lewis and Clark's expedition, which aimed to map the territory and identify its resources, including potential dangers.
The context of westward migration during this period was one of both caution and curiosity towards the unknown landscapes of the American frontier.