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

[EX Q]: Corms are undifferentiated, uniform, and contain _ rings when cut apart.
[EX A]: no

[EX Q]: Economists divide resources into _ basic categories of land, labor, capital, and management.
[EX A]: four

[EX Q]: Insects live in warm climates, hot climates, even sub _ climates.
[EX A]:
zero