Final answer:
The steps provided describe the process of respiration, which includes body movement indicative of inhalation and exhalation. The correct answer is option a.
Step-by-step explanation:
Understanding Respiration
The steps mentioned in the question are indicative of the process of respiration, which can be broken down into several key phases:
- Body moves forward - This could be describing the movement of air into the lungs during inhalation.
- Septa secreted - Although 'septa' are not secreted during respiration, this might refer to the production of pleural fluid which acts as a lubricant in the pleural cavity.
- Chamber starts emptying - This likely refers to the lungs during exhalation as air is expelled from the respiratory chambers.
- Restart - This implies the cyclic nature of the breathing process.
During respiration, gas exchange occurs across the alveoli in the lungs where oxygen (O2) is absorbed into the blood and carbon dioxide (CO2) is removed. This is a result of the difference in partial pressures, as dictated by Dalton's and Henry's laws. For example, O2 moves from the alveoli, where its partial pressure is higher, into the bloodstream, where its partial pressure is lower. Conversely, CO2 moves in the opposite direction, from the blood to the alveoli, where it can be exhaled.
As you inhale and exhale, the interplay of the diaphragm and chest muscles, along with the pleural fluid, facilitate the expanding and contracting of the thoracic cavity, making breathing possible. The correct option for the process described is A. Respiration.