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

Sodium chloride is an odorless white solid that is harmless unless consumed in large quantities.
What is an odorless white solid that is harmless unless consumed in large quantities?

In prokaryotes, a(n) genome is composed of a single, double-stranded dna molecule in the form of a loop or circle.
In prokaryotes, what is composed of a single, double-stranded dna molecule in the form of a loop or circle?

Narrow air passages make breathing difficult due to respiratory system disease.
What makes breathing difficult due to respiratory system disease?