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: Milk is a good source of all ____ nutrients.

A: three
****
Q: Copper has ____ naturally occurring isotopes.

A: two
****
Q: Astronomical observations suggest zero or close to ____ space-time curvature.

A:
zero
****