system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why is the skin on your face prone to blackheads and pimples so much more than the rest of your body?
gpt
The sebaceous gland produces sebum, which is an oily substance that moisturizes and protects the skin. Excess sebum production can block the sebaceous gland duct causing a comedo (a clogged hair follicle or pore), commonly known as a blackhead or whitehead. Unchecked a comedo can lead to an infection — acne.

In humans, sebaceous glands occur in the greatest number on the face and scalp, but also the shoulders, upper chest, and back.