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

For to synthesize glycogen purpose does liver use the excess carbohydrate.
For what purpose does liver use the excess carbohydrate?

Stringed instruments can help show the relationship between tension and frequencies in strings.
Stringed instruments can help show the relationship between tension and what in strings?

Vagina term is used to describe the muscular canal (approximately 10 cm long) that serves as the entrance to the reproductive tract.
What term is used to describe the muscular canal (approximately 10 cm long) that serves as the entrance to the reproductive tract?