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 have ____ incisors in the upper jaw where rodents have only two.
four

Marine biologists have ____ theories on why whales breach.
two

Pups consume an average of ____ liters of milk a day .

eight