TASK DEFINITION: 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.
PROBLEM: Hoatzin has typical foot with ____ toes forwards and one backwards.

SOLUTION: three

PROBLEM: Deer mice have four toes on the forefeet and ____ toes on the hind feet.

SOLUTION: five

PROBLEM: Scientists make monoclonal antibodies by fusing ____ kinds of cells.

SOLUTION:
two