Question

choose the best answer.
the ______ involved the purchase of land between the mississippi river and the rocky mountains.
mississippi treaty
louisiana treaty
louisiana purchase

Explanation:

The historical event that describes the U.S. purchase of land spanning from the Mississippi River to the Rocky Mountains is the Louisiana Purchase. The other options are incorrect: there is no major "Mississippi Treaty" for this land acquisition, and "Louisiana Treaty" is not the standard name for this event.

Answer:

Louisiana Purchase