Final answer:
Hair composition, physiological roles, nail composition.
Explanation:
Composition of Hair:
Hair is primarily composed of proteins such as keratin. It also contains water, lipids, pigments, and trace elements.
Physiological Roles of Hair:
- Protection: Hair acts as a physical barrier, protecting the scalp from UV rays, dust, and other environmental elements.
- Sensory Function: Hair follicles are connected to nerve endings, allowing for the sensation of touch.
- Thermoregulation: Hair helps regulate body temperature by trapping heat near the body or releasing it.
Nail Composition:
Nails are composed of keratin, the same protein found in hair. They consist of the nail plate, nail bed, cuticle, and nail root.
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