system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why are so many deep sea and cave creatures white? I know it's 'lack of sunlight' but why does lack of sunlight make things white?
gpt
If there is no light, then you don't need camouflage because nothing can see you.

If there is no UV light, you aren't getting sunburned and don't need melanin to protect your cells from damage.

It's just a case of less effort, same result, and over generations, those low effort strategies became the most common traits.