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: Women are _ times as likely to develop osteoporosis but men can also develop it.

A: four
****
Q: Bats actually echolocate using _ different systems, depending on the species of bat.

A:
three
****