What takes place during expiration?
- Adiaphragm muscles contract; pressure in thoracic cavity falls and then rises; volume of thoracic cavity decreases
- Bdiaphragm muscles relax; pressure in thoracic cavity rises and then falls; volume of thoracic cavity decreases
- Cdiaphragm muscles contract; pressure in thoracic cavity rises and then falls; volume of thoracic cavity increases
- Ddiaphragm muscles relax; pressure in thoracic cavity falls and then rises; volume of thoracic cavity increases