system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How does an avocado pit keep an avocado green even when removed and stored loosely in a container. What's the pit doing?
gpt
It doesn't. The only way to keep an avocado from going brown is to cut it off from oxygen. Or purge your fridge and fill it with nitrogen. 

The pit helps when left in the cut half because it's keeping a percentage of the surface area sealed away from oxygen. The concept of it doing anything to help when left loose nearby is nonsense. You'd be just as well off picking a rock out of your garden, scrawling "Avocado Preserver" on it, and keeping that in the container instead.