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

A desmosome is a cell structure that anchors the ends of cardiac muscle fibers together.
A desmosome is a cell structure that anchors the ends of what fibers together?

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

In the lungs, bicarbonate is transported back into the red blood cells in exchange for chloride.

In the lungs, bicarbonate is transported back into the red blood cells in exchange for what?