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

Resistors connected end to end are said to be in series.
Resistors connected end to end are said to be in what?

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

The amount of product that may be produced by a reaction under specified conditions is called theoretical yield.
What is the amount of product that may be produced by a reaction under specified conditions called?