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: New species are believed to arrive in the Mediterranean at the rate of _ to five annually.

A: four
****
Q: Contemplation is the stage in which people intend to change within the next _ months.

A:
six
****