The complete back-and-forth motion of an object is called a ? ?

well, that's easy; the answer's c, "it reduces contamination of the water and substrate of the estuary."

the elements of art are the visual tools that the artist uses to create a composition. these are line, shape, color, value, form, texture, and space.

the principles of art and design are balance, contrast, emphasis, movement, pattern, rhythm, and unity/variety.