Q. Which one of the following is a possibility for most of us in regard to breathing, by making a conscious effort ?
A) One can consciously breathe in and breathe out by moving the diaphragm alone, without moving the ribs at all
B) The lungs can be made fully empty by forcefully breathing out all air from them
C) One can breathe out air totally without oxygen
D) One can breathe out air through eustachian tubes by closing both the nose and the mouth
Explanation
[Solution from source] With conscious effort one can breathe by moving the diaphragm alone (abdominal breathing) while keeping the ribs still. The lungs can never be emptied completely because the residual volume always remains, and expired air still contains about 16% oxygen. Answer (1).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.