system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How do flies see things so much faster than us?

I’m out here trying to swat a fly and I swear it starts moving the millisecond I begin my swing, it’s crazy.
gpt
We are much bigger than flies. Even our brains are orders of magnitude bigger than them. So the time it takes for signals to travel from their eyes to their brains are much shorter because they're literally millimeters (or less) away.

Also, because their eyes and brains are much simpler, they need less time to process information before making a decision. And because they're so small, they've evolved to watch out for pray far larger than them going after them, hence their big, protruding eyes that can see in all directions.