What does it mean that the left hemi-diaphragm is concentrically effective for left thoracic rotation and extension?

• A. The left hemi-diaphragm is flat, which pulls on the spine. It takes your thorax and pulls it into left rotation and extension (i.e., left trunk rotation). The left hemi-diaphragm isn't effectively positioned for respiration.
• B. The left hemi-diaphragm is dome-shaped and supports respiration without affecting rotation.
• C. The left hemi-diaphragm promotes right rotation.
• D. The left hemi-diaphragm has no effect on thoracic rotation.

Answer: (A)