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

Bile acids, needed to emulsify lipids, are stored in the body in the gallbladder.
Where are bile acids, needed to emulsify lipids, stored in the body?

The nuclear envelope is a double-layered plasma membrane like the cell membrane, although without membrane proteins.
The nuclear envelope is a double-layered plasma membrane like the cell membrane, although without what?

Genes, or functional units of chromosomes, determine specific characteristics by coding for specific proteins.

What functional units of chromosomes determine specific characteristics by coding for specific proteins?