Who would you expect to have a greater lung capacity marathon runner or an average adult who smokes?

A marathon runner would be expected to have a greater lung capacity than an average adult who smokes.

Running is a cardiovascular exercise that requires a significant amount of oxygen to fuel the muscles. To meet this demand, marathon runners typically have larger lungs and more efficient respiratory systems than average adults.

Smoking, on the other hand, damages the lungs and decreases lung capacity. The smoke from cigarettes contains harmful chemicals that irritate and inflame the airways, causing them to become narrower and less elastic. This makes it more difficult for smokers to breathe and reduces their lung capacity.