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: Infertility affects one in ____ couples today.

SOLUTION: five

PROBLEM: Bullfrogs can live up to ____ years.

SOLUTION:
four