Knowledge: Carotene is a pigment found in many fruits and produced naturally in plants through a process called photosynthesis, while Eumelanin is synthesized via melanogenesis in cells called melanocytes.

Conversation:
I like brown hair
Oh, it's second only to black hair in how common it is.
Oh, I didn't know that. Is it different than other hair besides color?
Yes, brown hair has thicker strands than blond hair but thinner than red hair.
What about blonde?
Blond refers to the color of hair on males, while blonde is for females. At any rate, it has little of the pigment called eumelanin.
Oh really? How is eumelanin produced?

Response: Melanocytes are the cells responsible for synthesizing eumelanin via melanogenesis.