• itslilith@lemmy.blahaj.zone
    link
    fedilink
    English
    arrow-up
    3
    ·
    edit-2
    2 months ago

    Not true, topolgically the route

    left nostril -> sinus -> right nostril

    is another hole. So is

    any nostril -> sinus -> mouth.

    ears have the eardrum, so they don’t count.

    For the more formal definitions of topological holes, look up Betti numbers, I think there’s a VSauce video about it? For humans, the number of holes is at least 3 (but I’m sure I’m missing many more holes). Unless you’re missing the entire septum.