In which decade did the last human set foot on the moon?
a. 1960s
b. 1970s
c. 1980s
d. 1990s

Which of the following was not an important contribution made by the lewis and clark expedition? a. they made detailed descriptions of the terrain of the louisiana territory. b. they fostered relationships with native american tribes. c. they advanced the u.s. fur trade with european buyers. d. they secured the u.s. border of the oregon territory by negotiating a treaty with england.