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: Environmentalists warn that ____ turtle species are in severe decline from over-exploitation.

A: six
****
Q: Seismologists offer ____ major theories for the occurrence of large, deep earthquakes.

A: three
****
Q: Science is regulated by values of ____ different kinds.

A:
two
****