The anagen phase of a scalp hair is typically two to eight years. The anagen phase of an eyelash is typically:

Which type of melanin has two forms: black (DHI) and brown (DHICA)?  

What hormone causes vellus hair to transform into terminal hair in certain areas of the body during puberty?  

Name the skin cell type indicated.

Keratinocytes have a photoreceptor protein that detects UV light and is responsible for forming and positioning:  

Which form of ultraviolet light that strikes the Earth is primarily responsible for sunburn and contributes significantly to skin cancer?

All humans have roughly the same number of melanocytes in their skin and hair. The differences in skin color are the result of variation in the: Mark all that apply.  

At any given time, 85-90% of your scalp hairs are in the _______ phase of the hair growth cycle.

Vellus hairs are thinner because, unlike terminal hair, they lack a:

While Mary is eating lunch at McDonald’s, her car is stolen.