The _______ is a muscle in the bottom of the chest that bends downward to draw air in, and bows upward to force air out of the lungs. A. diaphram B. bronchi C. trachea D. heart
its the diaphragm. If you ever join a choir of some sort,your director will tell you to use your diaphragm to exhale air out to produce a louder and stronger sound.
