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: Inversions have the classic double loop at meiosis, and have ____ crossovers when heterozygotes.

SOLUTION: no

PROBLEM: Corporate mergers occur when ____ companies combine.

SOLUTION: two

PROBLEM: Guenons mature sexually at the age of ____ years.

SOLUTION:
four