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: Cells contain ____ families of small organic molecules.

SOLUTION: four

PROBLEM: Earthquakes are most frequent where ____ or more plates meet.

SOLUTION: two

PROBLEM: Some protozoans have ____ means of movement.

SOLUTION:
no