Given scientific fact as input, generate the question from this fact such that it can be answered from the input.

Circannual behavioral rhythms are linked to the yearly cycle of seasons.
What type of behavioral rhythms are linked to the yearly cycle of seasons?

Its temperature and ph best determines the health of a lake used as a source of freshwater.
Which best determines the health of a lake used as a source of freshwater?

The brain is the most complex organ in the human body.
What is the most complex organ in the human body?