What is one main characteristic of secondary sources intended for academic and students?

Why did president johnson decide not to run for reelection in 1968?

Abigail adams rescued important items from the white house, including a portrait of abraham lincoln, during the war of 1812. a. false b. true

Are people more motivated to change from positive or negative experiences, like slavery, womens rights, and any other historical movements/moments? i need factual information, not opinions.