"Exhaled air containing bubbles into water and reacts with water to produce carbonic acid. This will cause the solution to turn ."

Exhaled air containing Carbon dioxide bubbles react with water to form carbonic acid . The solution turn acidic and turn from green to yellow.

Explanation:

Exhaled carbondioxide bubbles reacts with water to form carbonic acid, the solution will turn acidic. Carbonic acid is a weak acid that decrease pH. An indicator of it shows that the solution turns from green to yellow.

Co2+ H2O= H2Co3.

The solution then dissociate to give H ion and hydrogen carbonates ion.

answer; the code in musculoskeletal system subsection is associated with deep tissue possibly to the bone;