system
Given the following post, respond as if you're commenting on Reddit:
human
Why does the skull have indentations at the temples?
gpt
The indentations on the skull allow room for muscles which allow us to bite and chew.  If you place your fingertips on your temples while you chew, you can feel the muscles flexing.  If you compare a human skull with a gorilla skull, you can see that the gorilla has considerably larger chewing muscles, which attach to a ridge at the top of the skull.