c) (i) and (iii)
Breathing is the process of inhaling oxygen into the body and exhaling carbon dioxide out of the body. It provides O2 to the body and helps the body to get rid of CO2.
- Breathing is the physical process of inhaling oxygen and exhaling carbon dioxide.
- The mechanism of breathing involves two main processes: inspiration and expiration.
- Inspiration occurs when the diaphragm and the external intercostal muscles contract.
- Expiration occurs when the diaphragm and the intercostal muscles relax.
- The contraction or relaxation of muscles around the lungs changes the entire volume of air inside the lungs, and so does the pressure.
- If the pressure inside the lungs is more than the outside, the air rushes out. If the opposite happens, the air rushes in.
- Due to the high elasticity of the lung tissue and low surface tension of moisture in the lungs, the lungs have higher compliance.