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.

[EX Q]: Rabbits have ____ incisors in the upper jaw where rodents have only two.
[EX A]: four

[EX Q]: Human gestation is divided into three trimesters of ____ months each.
[EX A]: three

[EX Q]: Females give birth to calves every ____ to three years.
[EX A]:
two