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: Tetrads come in ____ shapes.

A: seven
****
Q: Mollusks have one or ____ hearts.

A: two
****
Q: Ruminants have an even number of toes on each foot and a stomach with either three or ____ chambers.

A:
four
****