Final answer:
Yawning, chewing gum, and swallowing can forcibly open the eustachian tube.
Step-by-step explanation:
The nurse teaches the client that yawning, chewing gum, and swallowing are activities that may forcibly open the eustachian tube.
Yawning opens the eustachian tube by stretching the muscles that control its opening. Chewing gum and swallowing also open the eustachian tube by activating the muscles in the throat and jaw.