In this task, find the most appropriate number to replace the blank (indicated with _ ) and express it in words.

[EX Q]: Rainforests cover less than _ percent of the Earth's surface.
[EX A]: two

[EX Q]: Most biologists divide the living world into _ Kingdoms.
[EX A]: five

[EX Q]: Muscle burns _ times the calories that fat does.
[EX A]:
eight