Primary sources may be objects (artifacts, tools, weapons, inventions, fashions, uniforms), images (photographs, film, video), audio (oral histories, music, interviews, speeches,) or documents (books, letters, journals, diaries).
A primary source gives you direct access to the subject of your research. Secondary sources provide second-hand information and commentary from other researchers. Examples include journal articles, reviews, and academic books. A secondary source describes, interprets, or synthesizes primary sources.
The Missouri Compromise was a strategic solution by Henry Clay to keep the slave and free states equal. It prevented conflict between the north and south as both regions had equal representation in congress regarding state senate votes