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: Green lines represent the boundaries between the ____ hemispheres.

SOLUTION: two

PROBLEM: Atoms are extremely small, on the order of a few ____ billionths of a meter.

SOLUTION: ten

PROBLEM: Land plants share ____ key features only with the charophyceans.

SOLUTION:
four