Given a sentence, fill out the missing word with a 'no' or a number (between zero and ten). You should write the numbers with english alphabet, like: four instead of 4.

Sapsuckers are a group of ____ species known for literally drinking the sap of trees.
four

Titanium is found in column ____ along with chemically similar zirconium, hafnium, and thorium.
four

Comets really have ____ visible tails.

two