Mammals have numerous adaptations of the circulatory, respiratory and digestive systems that allow them to maintain a high metabolic rate. Describe five such structures and indicate the role of each in maintaining a high metabolic rate. Again, many potential correct answers. As per the question, each feature had to be a structure . The typical mammalian brown color results from alternating stripes of eumelanin and pheomelanin along each hair shaft.
White coloration derives from the absence of either pigment.
This results in an increase in the insulative capacity of the hair. There are also sebaceous glands associated with the hair follicle that secrete oil.