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: Cockroaches have six legs, ____ antennae and some have wings.

A: two
****
Q: Sexual maturity occurs at ____ to four years for females and four to five years for males.

A: three
****
Q: Ozone is made up of ____ oxygen atoms.

A:
three
****