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.

Rabbits have a total of ____ teeth rather than four, as is characteristic of rodents.
six

Light chains exist in ____ classes, lambda and kappa.
two

Compact bone is very strong and dense, having ____ spaces within it other than the Haversian canals.

no