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.

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

Nymphs go through ____ instars and a pupa stage before reaching adulthood.
three

Hyperlipidemia usually occurs within the initial two to ____ weeks.

four