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.

Q: Naiads have ____ caudal filaments and external gills.

A: two
****
Q: Early childhood refers to the time period between birth and ____ years of age.

A: eight
****
Q: Trees become susceptible to injury when they reach a height of about ____ feet.

A:
three
****