Practice question

Correct option is C, Diaphragm and external intercostals. In Lung Volumes, Capacities and Regulation, the accurate description is Diaphragm and external intercostals, and that is what you should commit to memory. Keep the definition tight and the role clear — the functional job described in the stem is exactly what Diaphragm and external intercostals does in Lung Volumes, Capacities and Regulation. Then Diaphragm and external intercostals is the answer you can defend. Check yourself by covering the options and writing the answer first, then matching the letter — that builds confidence. If the wording feels dense, translate it into everyday language first, then map that plain sentence back onto Diaphragm and external intercostals.