system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What are freckles and why do we get them?
gpt
When the sun hits your skin, the outside layer of your skin thickens a little bit. Some cells understand that event as a sign to produce a dark pigment (melanin). This pigment helps to protect the skin from the sun.

People with lighter skin have less melanin on their skin, so, when the pigment is produced they often get freckles instead of an even tan.