OK, time for some detective work. This microphotograph is comparing two things. What are they?
These are two hairs. The hair on the left is my hair. You can see the hollow tube inside the hair that contain pigment as well as many air bubbles. The bubbles diffuse light, making the hair look white or gray. The hair on the right is a white hair from our dog Junie Moon. Instead of getting its white color from air bubbles, this hair looks white because of its lack of pigment.