How did the battle of marathon pave the way for alexander of macedon?

A battle was fought between the Athenians and the Persians at the plain of Marathon in 490 B.C. This battle marked the defeat of the Persian invasion on Greek. The death of Darius's (king of Persia) proved Alexander as, "the Great King". While Athens recovered in decades, they (Athens and the Greek city-states) were never able to regain their full power, this paved the ways to the rise of Macedonian under Philip II. Alexander the Great( son of Philip II) united all the Greeks under his leadership. Their rise to power meant that the Athenians could not regain their power as they had in the 5 century BCE. Therefore Macedonians under the leadership of Alexander started conquering land in Asia Minor, Syria and extended their empire as far as Punjab in India.

the indians crossed artificial boundaries, setting the stage for conflict

probably that america is racist