After the boarding has closed, what three actions should be taken?

After boarding has closed, the appropriate actions are to arm the door(s), cross-check, and stand by for an all call. This procedure is critical for ensuring the safety and readiness of the aircraft before takeoff.

Arming the door(s) is essential for the preparation of an emergency evacuation. By arming the doors, the crew ensures that the evacuation slides will deploy correctly in the event that an emergency arises.

Cross-checking involves verifying that all doors are properly armed and that the cabin is ready for departure. This step provides an added layer of assurance that all necessary precautions have been taken and that the safety measures are in place.

Standing by for the all call signals the crew's readiness to the flight deck, allowing communication between cabin crew and the pilots. This ensures that everyone is aware of the aircraft's status and is prepared for the next steps in the departure process.

This sequence of actions prioritizes passenger safety and operational readiness, which are paramount for a successful departure.