Texture is very prominent in the wooden bridge. the other elements are line (converging gaps between the wood planks), form (the light from the top gives volume to the bridge), and blank (contrast between light on top and dark at the bottom).

Color

Explanation:

Texture is very prominent in the wooden bridge. The other elements are line (converging gaps between the wood planks), form (the light from the top gives volume to the bridge), and COLOR (contrast between light on top and dark at the bottom).

The answer is COLOR.

Explanation: Just to elaborate a little on the answer, it could also be added that the contrast between light and dark, particularly when is very dramatic, is known in art as chiaroscuro (an Italian word meaning "clear/light and dark"), although this is a more specific term. Color is a very important artistic element, and it refers to the use of hues in art. Since the excerpt is talking about contrast between light and dark, it may be specifically referring to color value, if the bridge only features one color. However, when speaking of color, there are many different elements you can describe and analyze: tone, saturation, shade, and so on.

perimeter = 2l +2w, divide total perimeter by 2 for total length of 1 side and 1 width

172/2 = 86 (  total for 1 side and 1 width)

86-24 = 62 (since length is 24 ft longer subtract 24 then divide by 2 for width)

62/2 = 31

width = 31 feet

length = 31 +24 = 55 feet

check: 31*2 = 62, 55*2 = 110,  110+62 = 172