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: Pacific salmon leave their home stream, swim out to sea and return ____ to six years later to spawn.

SOLUTION: one

PROBLEM: Copper has ____ naturally occurring isotopes.

SOLUTION: two

PROBLEM: Absolute pressure is based on a ____ reference point, the perfect vacuum.

SOLUTION:
zero