Meriwether Lewis and William Clark helped open the American frontier to settlement by displacing several American Indian groups.
expanding American knowledge of the continent.
negotiating an important treaty with France.
discovering a river route to the Pacific Ocean.
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the causes of the dust bowls were severe droughts,   lands became dry and hard, temperature was higher than usual, hot and dry conditions killed crops, high winds. because of those factors, the winds kicked up dry soil and created clouds of dust.

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because the land run of 1889, although not without precedent in the history of the west, further, their men were aboard the first trains, ready to jump off and begin staking their claims. oklahoma city, edmond, and guthrie were all so affected.