system
Given the following post, respond as if you're commenting on Reddit:
human
Why haven't species developed more eyes?

It may sound like a stupid question but it seems odd to me that so many animals have only two eyes. I know a lot of herbivores have developed eyes on the side of their head to allow them to see predators from behind them, why haven't they just developed eyes on the back of their heads, so as not to have decreased visibility in front of them?
gpt
Species don't develop new traits specifically to accommodate some need.  Mutations are entirely random and only "stick" if it increases survivability long enough to become homogeneous among the population.