system
Given the following post, respond as if you're commenting on Reddit:
human
Why don't we send a group to colonize the Moon as practice before trying to go to Mars?

Wouldn't it be smart to send a team to the moon to live there for a while to learn how to create a living space on a different planet? That way if any problems arise, we'll be able to find a fix for them before we try anything on Mars, and we wouldn't be a month away from safety.
gpt
Supplies such as oxygen and water would need to be manufactured on site.

This is easier on Mars. Mars, for example, has polar ice caps which can be melted for water, and oxygen can be extracted from water electrically. The moon has nothing and would be harder. You can't fit enough oxygen and water for a colony in a supply rocket.