Which would be considered a secondary source about the assassination of abraham lincoln?

What refers to the division of power among the three branches of government

Why was the u.s. annexation of hawaii delayed until william mckinley became president? a: the rebels who overthrew queen liliuokalani opposed u.s. annexation. b: the senate did not approve the treaty of annexation until mckinley entered the white house. c: supporters of the nationalist cause were in the majority in hawaii until 1898. d: mckinley’s predecessor, grover cleveland, refused to sign the treaty of annexation.

Word does jefferson use in opening of the second paragraph that means "obvious? "