What is a "sit-in" and why did civil rights activists do this?

Sit-in movement, nonviolent movement of the U.S. civil rights era that began in Greensboro, North Carolina, in 1960. The sit-in, an act of civil disobedience, was a tactic that aroused sympathy for the demonstrators among moderates and uninvolved individuals.

the branch of biology that deals with the normal functions of living organisms and their parts.

the way in which a living organism or bodily part functions.