Answer:
The mood of the poem "The Negro Speaks of Rivers" is dignified and wise. Langston Hughes establishes a connection between the ancient rivers of the past, which birthed civilization, to the prominent Mississippi, where slaves were traded throughout America
A complex sentence: consisting of many different and connected parts.
I don't know the context, but I believe the answer must be predicate adjective. If your sentence goes something like "This song is popular", popular is a predicate adjective because it goes together with a linking verb ("is"), and modifies the subject ("song"), telling us what the subject is, and not what it does.