At work we somehow landed on the topic of how many holes a human has, which then evolved into a heated discussion on the classic question of how many holes does a straw have.
I think it’s two, but some people are convinced that it’s one, which I just don’t understand. What are your thoughts?
No, gas exchange is by simple diffusion across the skin and gut. No ears or eyes per se, just some photosensitive cells in slight depressions on the head. Planaria are pretty simple as far as animals go.