why did John Lewis think the NAACP is too conservative? and how does John Lewis Idea differ from Thurgood Marshall? (I will Give Brainiest and answer must be thoroughly answered)

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.