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: Copper has ____ naturally occurring isotopes.

SOLUTION: two

PROBLEM: Lancelets display all ____ of the vertebrate characteristics throughout their lives.

SOLUTION: four

PROBLEM: Golden eagles acquire their adult plumage within approximately ____ years.

SOLUTION:
five