Clare's tan is primarily due to an increase in which substance in her skin?

• A. Carotene
• B. Melanin
• C. Collagen
• D. Elastin

Answer: (B)

A tan occurs primarily as a result of increased levels of melanin in the skin. Melanin is the pigment that gives skin its color and protects it from the damaging effects of ultraviolet (UV) radiation from the sun. When skin is exposed to UV light, melanocytes (the cells responsible for melanin production) become more active and produce more melanin as a response to protect the deeper layers of the skin from potential damage.

The increase in melanin serves to absorb and dissipate UV radiation, thus reducing the likelihood of DNA damage that could lead to skin cancers. This response is a natural defense mechanism and is why individuals develop a darker skin tone after sun exposure.

Other substances mentioned, like carotene, collagen, and elastin, do not play the primary role in skin tanning. Carotene contributes to a yellow/orange pigment but is not the main factor for tanning. Collagen and elastin are proteins that provide structural support and elasticity to the skin but are not involved in the pigmentation process related to tanning. Thus, the correct answer demonstrates a fundamental aspect of the physiological response of the skin to UV exposure, highlighting the protective role of melanin.