Read the following statements carefully. I. Normal expiration involves the relaxation of the diaphragm and external intercostal muscles. II. Humans have the ability to increase the strength of inspiration and expiration with the help of additional muscles in the abdomen. III. Inspiration occurs when the intrapulmonary pressure is higher than the atmospheric pressure. IV. An increase in pulmonary volume leads to an in

Step-by-step solution

Statement I is correct. Normal expiration is a passive process that occurs due to the relaxation of the diaphragm and external intercostal muscles, which reduces thoracic volume. Statement II is correct. We have the ability to increase the strength of inspiration and expiration with the help of additional muscles in the abdomen. Statement III is incorrect. Inspiration occurs when the intrapulmonary pressure is less than the atmospheric pressure (negative pressure in the lungs). Statement IV is incorrect. According