Given a sentence, fill out the missing word with a 'no' or a number (between zero and ten). You should write the numbers with english alphabet, like: four instead of 4.

Rabbits can live to be around ____ years old or older.
ten

Prions are protein molecules which have ____ metastable states.
two

Raptors usually have ____ talons pointing forward and one talon pointing backward.

three