By what action could the pressure gradient between the middle and the outer ear be balanced?
Domanda 317, Human Performance and Limitations - ATPL - Airline Transport Pilot license
| By breathing out. |
| By breathing in. |
| By coughing. |
| By swallowing. |
| By breathing out. |
| By breathing in. |
| By coughing. |
| By swallowing. |
