instruction:
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.
question:
Natural ytterbium is a mixture of ____ stable isotopes, with seven other unstable isotopes known.
answer:
seven


question:
Ozone is formed of ____ atoms of oxygen.
answer:
three


question:
Millipedes have ____ per body segment and they have lots of body segments.
answer:

four