system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5:Why do we have so many blackheads on our nose?
gpt
A blackhead is a clogged hair follicle. Oil and a skin protein called keratin combine to clog the follicle. When the combination is exposed to oxygen, it turns black.

You have a lot of oil glands on your nose because they protect your skin from the sun and other environmental hazards. Oil tends to collect on the side of your nose because of gravity and the way it's shaped. Furthermore, you have more oil in your hair, hands, etc. People touch their nose a lot, which moves even more oil to their nose.

Your nose has keratin because it is the main structural component of skin cells (and hair.) Your body is constantly making new skin cells and the old ones slough off. This helps protect you from UV sun rays that cause skin cancer, and other environmental dangers.