Either you hurt it badly so it came of or there is a new layer of nail under.
I think it is a type of ocd. Where you want to pull off your toe nails and sometimes pull out eye lashes .
No. Toenails, like hair, are dead tissue.
Keratin
It is probably just old blood (in other words, a bruise) from where you banged your toe at some point. It will go away as your toenail grows out. It is not dangerous at all.
a protein that makes up finger and toenails
It's not.
Well, if your cockatiel's toenails are falling off, it probably has some kind of sickness. take him/her to the vet and see what he says.
Your toenails fall off
Yes, if you trim them off your toe first.
Yes it is normal
Too small shoes.
It means... you are going insane.
Peanut butter
use a planner to plan them off
It regrows... The same is true for toenails.
Trauma to the toenail can cause it to die off. An infection within the nail can also cause it to die off.
Toenails help you balnce.