system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do fruits like apples or bananas get "bruised" when bumped or dropped?
gpt
Its usually an example of the skin of the fruit being lightly damaged, which allows the organic chemical compounds in the fruit to react to outer factors.

The bruising is an act of these compounds oxidizing, which takes on a brownish color.