The ventilation movements of the lungs in mammals are governed by

Explanation

All options are explained below: a) Muscular walls of lung: The walls of the lungs themselves do not play a direct role in governing ventilation movements. The lung tissue is elastic and expands or contracts in response to changes in pressure created by the muscles involved in breathing. b) Diaphragm: The diaphragm is a major muscle responsible for the process of breathing. When the diaphragm contracts, it moves downward, increasing the volume of the thoracic cavity, which leads to inhalation. When it relaxes, it moves upward, decreasing the thoracic cavity's volume, which results in exhalation. c) Costal muscles:Costal muscles, also known as intercostal muscles, are located between the ribs. They assist in the expansion of the ribcage during inhalation and play a significant role in the breathing process. When they contract, they lift the ribs, expanding the thoracic cavity and aiding in inhalation. d) Both (B) and (C) (Correct Option): The correct answer is both the diaphragm (muscle located below the lungs) and the costal muscles (intercostal muscles). Together, these muscles work in a coordinated manner to control ventilation movements in the lungs. The diaphragm primarily controls the vertical expansion and contraction of the thoracic cavity, while the costal muscles assist in expanding the ribcage horizontally during inhalation. This combination of muscular actions allows for effective breathing. Correct Option: D. Both (B) and (C) are involved in governing the ventilation movements of the lungs in mammals. Summary: The ventilation movements of the lungs in mammals are primarily governed by a combination of the diaphragm and costal muscles (intercostal muscles). The diaphragm controls vertical expansion and contraction, while the costal muscles assist in the horizontal expansion of the thoracic cavity during inhalation. This coordinated action allows for efficient breathing. The walls of the lungs themselves do not play a direct role in this process.