system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What is the difference between mixing and mastering a song?
gpt
The most basic explanation is mixing is making adjustments to the individual tracks/instruments so that they mesh together best (adjusting volume of tracks against each other, adjusting eqs or the panning of certain tracks.)

Mastering is adding whatever final touches/effects to the track as whole once the individual tracks have been mixed together. This could be making the track fade out, adjusting the overall eq, or adding reverb to the entire track.