TASK DEFINITION: In this task, find the most appropriate number to replace the blank (indicated with _ ) and express it in words.
PROBLEM: Blood is made up of _ parts.

SOLUTION: four

PROBLEM: Presta valves are the skinnier of the _ valve types.

SOLUTION: two

PROBLEM: Attainment designation refers to the levels of _ criteria pollutants in the air.

SOLUTION:
six