Which instruments are used to verify and crosscheck the attitude of the airplane?

The correct choice includes the altimeter, heading indicator, airspeed indicator, and the turn coordinator because these instruments provide critical information that helps pilots verify and crosscheck the airplane's attitude effectively.

The attitude indicator shows the aircraft's orientation relative to the horizon, indicating whether it is climbing, descending, or turning. However, relying solely on the attitude indicator may not provide a full picture of the airplane's performance. By cross-referencing it with the altimeter, a pilot can determine altitude changes. The heading indicator informs the pilot of the aircraft's direction. The airspeed indicator provides data about the speed at which the aircraft is traveling, which can be influenced by pitch changes. Lastly, the turn coordinator helps the pilot understand the rate of turn, which is essential when assessing the aircraft's bank angle relative to the horizon.

Using this combination of instruments allows a pilot to have a comprehensive understanding of the aircraft's orientation and ensures that all aspects of flight are being considered, leading to better situational awareness and safer flying.