Human skin is an example of:
organ system
tissue
organism
organ

protein makes up the building blocks of organs, muscles, skin, hormones and pretty much everything that matters in your body.

some choices are:

peanut butter

seeds

eggs

yogurt

meats

fish

so pretty much meat, dairy, nuts, and grains.

answer; the code in musculoskeletal system subsection is associated with deep tissue possibly to the bone;