The correct answer to this open question is the following.
Although there are no options attached we can say the following.
In addition to mapping the Louisiana purchase, Louis and Clark also contributed to Americans' knowledge about the west part of the North American territory and its possibility to be settled.
After the Louisiana Purchase of 1803, US President Thomas Jefferson ordered the Lewis and Clark expedition to explore the newly acquired lands. The task was for Meriwether Lewis who, in 1804 accepted the help of William Clark to lead the exploration of the unknown territories.
After two years and almost 9000 miles of the journey, both explorers returned to Washington D.C: to debrief the president.
