system
Given the following post, respond as if you're commenting on Reddit:
human
Why is vision grainy at night or in dark areas?

At night time why does human vision appear grainy?
gpt
Because your central vision (where you have color perception) is high resolution (higher density of light-sensing cells) but low-sensitivity (requires more light to detect) whereas your peripheral vision is low resolution and high sensitivity (and so works better in low light than color vision).

From an evolutionary perspective, because the color of the bear that is going to kill you is irrelevant, whereas the color of the fruit you are about to eat is important.