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.

Female mealybugs have only ____ nymphal stages.
three

Body temperature attains ambient levels within four to ____ hours.
six

Squirrels have ____ teeth in the front of their mouth that constantly grow throughout their lives.

four