Hair that has been pulled out from the roots can grow back under which of the following circumstances?

• A. The cortex has not been destroyed
• B. The cuticle has not been destroyed
• C. The papilla has not been destroyed
• D. The medulla has not been destroyed

Answer: (C)

Hair regrowth after being pulled out depends on the dermal papilla at the base of the follicle. This structure supplies blood and growth signals to the follicle, so as long as the papilla remains intact, a new hair can form from the follicle. The other parts listed—the cortex, cuticle, and medulla—are parts of the hair shaft itself; damage to them affects the hair that grows later or its appearance, but does not prevent new hair from forming as long as the papilla is still nourishing the follicle. If the papilla were destroyed, regrowth would be unlikely.