What role can sulfur play in the makeup of amino acids and proteins?

Sulfur is part of the structure of some amino acids and proteins.

Explanation:

Sulfur enters the disulfide layers in proteins and is responsible for their spatial structure. Many proteins, in order to perform their function, need a stable spatial form (Enzymes, for example.). Because disulfide bridges form strong bonds between amino acids, this structure remains strong and stable to perform its function.  In addition, sulfur is present in the amino acids cystine, cysteine and methionine contained in proteins. Proteins are the compounds in which most of S and N are incorporated. Sulfur content in proteins is 1 g / kg and N is 15 times higher.

i'm thinking (a) to keep sand in place; ////////////

explanation: a sand fence or sandbreak, like a snow fence, is used to force windblown, drifting sand to accumulate in a desired place. sand fences are employed to control erosion, sand dune stabilization, keep sand off roadways, and to recruit new material in desert areas.

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.