This document discusses hair and fibers in forensic science. It provides details on: - The structure and composition of hair, including the cuticle, cortex, and medulla layers. Hair characteristics like color, length and shape can indicate where on the body it came from. Nuclear and mitochondrial DNA can be extracted from hair roots or cuticles. - Fibers are long thin strands that can be spun into yarn and woven into fabrics. Matching unique fibers between a victim and suspect's clothing can provide evidence of contact. - Both natural fibers like cotton and wool and synthetic fibers like nylon and polyester are important in forensic analysis and can be identified under a microscope.