TASK DEFINITION: In this task, find the most appropriate number to replace the blank (indicated with _ ) and express it in words.
PROBLEM: Animals develop either two or _ embryonic germs layers .

SOLUTION: three

PROBLEM: Weasels reaching _ to six years are regarded as fully mature.

SOLUTION: five

PROBLEM: Cetaceans are noted for their play behavior, seemingly pleasurable activities with _ serious goal.

SOLUTION:
no