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

[Q]: Titanium is found in column _ along with chemically similar zirconium, hafnium, and thorium.
[A]: four

[Q]: Territorial groups consist of one supermale or terminal male and _ to three females.
[A]: one

[Q]: Humans have _ lungs, each fed by one bronchus.
[A]:
two