Question

question 9
altmeters are used to indicate altitude in flight and are calibrated in?
○ psi
○ mercury
○ thousands of feet

Explanation:

Altimeters measure altitude, and they are calibrated to show altitude in units related to height. "Thousands of feet" is a unit for measuring altitude (height above a reference), while "psi" (pounds per square inch) is a pressure unit and "mercury" (like inches of mercury) is a pressure - based unit for barometric pressure, not directly for altitude measurement in the context of altimeter calibration for flight altitude indication.

Answer:

thousands of feet