Final answer:
Sacagawea, a young woman who was kidnapped and sold to a French fur trader, played a crucial role as an interpreter and diplomat during the Lewis and Clark Expedition. Her presence and her infant helped to convey the peaceful intentions of the expedition to Native American groups they encountered.
Step-by-step explanation:
Lewis and Clark Expedition was an important exploration that took place in the early 19th century. Sacagawea, who was kidnapped and sold to a French fur trader named Toussaint Charbonneau, joined the expedition and made significant contributions as an interpreter and diplomat. Her presence, along with her infant, helped to dispel any fears among Native American groups, showing the expedition was not hostile.