During the process of breathing, which of the following events specifically causes an increase in the volume of the thoracic chamber in the dorso-ventral axis?

Step-by-step solution

According to NCERT, inspiration is initiated by the contraction of the diaphragm, which increases the volume of the thoracic chamber in the antero-posterior axis. The contraction of external intercostal muscles lifts up the ribs and the sternum, causing an increase in the volume of the thoracic chamber in the dorso-ventral axis. Relaxation of these muscles leads to a decrease in thoracic volume (normal expiration), while the contraction of internal intercostal muscles is involved in forced expiration. Answer: Contr