Answer:
Species / People.
Step-by-step explanation:
The hairs are made up of three distinct layers which are cuticle, medulla and cortex. Cuticle is the outer layer in the medulla is located at the center. The cuticle and medulla can help in distinguishing hairs among different species since their properties are much different but they do not offer too much information for distinguishing hairs between to organism from the same species like two people.
I hope this answer helps.