system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why does my banana ripen at superspeed when it's in my backpack?
gpt
Bananas are a fruit that if it's surrounded by the chemicals it emits, will ripen much faster (you can turn green bananas to yellow quickly if you wrap them in a plastic bag).  In an open area, these chemicals spread out and the fruit ripens at a more 'normal' rate.