Why was Alexander the Great able to conquer the Persian state?

Alexander the Great defeated the Persian state thanks to a more combat-ready army and his tactics. The Persian army was large, but poorly armed, unprofessional and lacked good discipline. In addition, it consisted of various conquered peoples who did not understand each other.
The Macedonians were well armed, trained, and knew how to follow orders. Alexander himself took part in battles, served as a role model for his soldiers. The structure of the phalanx also gave the Macedonians an advantage.