#ELI5 Why is water see through?

I'd never thought about it like this. Wow.

@Jdreben @jpm all the early creatures that couldn’t see through water got eaten by ones who could.
@jpm @Unixbigot @Jdreben there was a period where exactly that happened.
It didn’t last very long.
@BenAveling @jpm @Jdreben ah yes the Omnomnomian era
@Unixbigot @jpm @Jdreben Sometimes known as the Cambrian Explosion, but yes, that's probably a more accurate description.
@BenAveling @jpm @Jdreben indeed, the fascinating time of such enigmatic wonders as anomalocaris, hallucinogenia, and holyfuckitsallteethiea.