The three main elements that include the Exposure Triangle would be Shutter speed, Aperture, and ISO.
determines how long the shutter stays open as the picture is taken. Shutter speeds are in seconds or fractions of a second. Each speed number halves the amount of light of2, 1, 1/2, 1/4, 1/8, 1/15, 1/30, 1/60, 1/125, 1/250, 1/500, 1/1000, 1/2000, 1/4000, 1/8000 .
an open, hole, or a gap.
A space thru which light passes throught that one spot.
Understanding Exposure: The Exposure Triangle with Mark Wallace