In this task, find the most appropriate number to replace the blank (indicated with _ ) and express it in words.

Q: Monsoons coming every three to _ years can add almost a foot of water to the mountain's surface.

A: seven
****
Q: Ferrets bite in _ manners.

A: two
****
Q: Cephalopods are the only mollusks with a closed circulatory system with _ hearts.

A:
three
****