What refers to the speed with which light areas turn into shadow areas?

Stanly Kubrick’s movie, 2001: A Space Odyssey, is a great illustration of André Bazin’s observation that the function of the cinema is

A. to emphasize the human being over the environment they inhabit. B. to bring to light certain details that the stage would have left untreated. C. to emphasize real locations and settings over artificial studio sets. D. to be the equal in every regard of the theater and the stage play.

Sticks of chalk, pastel, and crayon are all made by combining pigment with ________.

Fill in the blank(s) with the appropriate word(s).