Final answer:
The Preparatory Command is the part of drill commands that alerts and prepares troops for an upcoming movement, followed by the Command of Execution to carry out the move.
Step-by-step explanation:
In drill commands, the part that alerts the troops or subordinates and prepares them for the movement they are about to execute is known as the Preparatory Command. This command gives advance notice of a drill move that will be executed and ensures that everyone understands what is expected before the move is carried out. The Preparatory Command is followed by the Command of Execution, which is the order given to execute the move immediately.