NEETZoologyBreathing and Exchange of Gases
Match List-I with List-II. List-I List-II (A) Contraction of diaphragm (I) Increases thoracic volume in dorso-ventral axis (B) Contraction of external intercostal muscles (II) Forceful expiration (C) Relaxation of diaphragm and external intercostal muscles (III) Increases thoracic volume in antero-posterior axis (D) Contraction of abdominal muscles (IV) Normal expiration Choose the correct answer from the options giv
Options
- A(A)-(I), (B)-(III), (C)-(IV), (D)-(II)
- B(A)-(III), (B)-(I), (C)-(II), (D)-(IV)
- C(A)-(I), (B)-(III), (C)-(II), (D)-(IV)
- D(A)-(III), (B)-(I), (C)-(IV), (D)-(II)
Correct answer
D. (A)-(III), (B)-(I), (C)-(IV), (D)-(II)
Step-by-step solution
The mechanism of breathing involves changes in the volume of the thoracic cavity: Contraction of the diaphragm increases the volume of the thoracic chamber in the antero-posterior axis. Hence, (A) matches with (III). Contraction of the external intercostal muscles lifts up the ribs and sternum, increasing the thoracic volume in the dorso-ventral axis. Hence, (B) matches with (I). Relaxation of the diaphragm and external intercostal muscles returns the diaphragm and sternum to their normal positions, reducing thorac