Final answer:
During a forced expiration, the internal intercostals and abdominal muscles contract. These muscles work together to push air out of the lungs more forcefully than during quiet breathing. The correct answer is e) internal intercostals and abdominal muscles.
Step-by-step explanation:
In an active, or forced, expiration, the muscles that contract are internal intercostals and abdominal muscles. During a forced exhalation, these muscles work together to forcefully expel air from the lungs. The internal intercostals help by drawing the ribs together and compressing the rib cage, while the abdominal muscles contract to push the abdominal organs upward against the diaphragm. This coordinated action propels air out more quickly and with greater force than during passive expiration.
It's important to note that during normal breathing, or quiet expiration, these muscles are not primarily engaged. Instead, air leaves the lungs passively as the diaphragm relaxes. However, when additional force is needed, as in coughing or vigorous physical activity, the internal intercostals and abdominal muscles become actively involved.
Therefore, the correct answer to the question is e) Answers b and d are correct: b) internal intercostals and d) abdominal muscles.