system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5:Why do some (Cessna 172 for example) planes need a fuel mixture which is adjusted by the pilot, but a cars fuel air mixture is automatic?
gpt
Combustion engines rely on having the correct air to fuel mixture ratio.

The air pressure (and therefore Oxygen amount) at ground level is fairly static, so maintaining the correct air/fuel mixture ratio manually is unneeded.

However, at higher and higher altitudes, the air pressure , and therefore oxygen content lowers, and therefore in order to maintain the correct ratio of air to fuel for combustion *at different altitudes* requires the pilot to be able to set this mixture ratio manually.