All the hair on your body has a life cycle. It grows, falls out , lays dormant a little while then grows again. That is why people lose hair every day but don't go bald. It is also why you have hairs of different lengths all the time. The hair on your head, your eyebrows and the hair on your arms are all programed to grow for different lengths of time before they fall out.
canuckbuck2020 t1_iy1uyrb wrote
Reply to eli5: Different body hairs grows differently by kenito225
All the hair on your body has a life cycle. It grows, falls out , lays dormant a little while then grows again. That is why people lose hair every day but don't go bald. It is also why you have hairs of different lengths all the time. The hair on your head, your eyebrows and the hair on your arms are all programed to grow for different lengths of time before they fall out.