The most abundant protein in the human body is ___, made by fibroblasts.
a Fibroblasts is a cell in connective tissue that produces collagen and other fibers.
Collagen is the main structural protein found in animal connective tissue, yielding gelatin when boiled.
Keratin is a fibrous protein forming the main structural constituent of hair, feathers, hoofs, claws, horns, etc.
Melanin is a dark brown to black pigment occurring in the hair, skin, and iris of the eye in people and animals. It is responsible for tanning of skin exposed to sunlight.
Hemoglobin is a red protein responsible for transporting oxygen in the blood of vertebrates. Its molecule comprises four subunits, each containing an iron atom bound to a heme group.
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