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.

[Q]: Plants have roots for ____ main reasons.
[A]: two


[Q]: Luminosity decreases by almost four orders of magnitude in approximately ____ million years.
[A]: five


[Q]: Critters are our handmade teddy bears in ____ sizes.
[A]:
three