Explain how the persian empire was able to maintain an efficient system of communication.

The Persians built a system of well maintained roads which facilitated the rapid transit of military and government personnel. One particular road was called the Royal road that stretched from Sardis to Susa . The Persians  established way stations at intervals equipped with fresh horses for the King's messenger.

The Assyrian system of communication was so efficient  and effective that a provincial governor anywhere in the empire except Egypt could ask a question and receive an answer within a week. 

ummm? is that supposed to be a question or a but this is a reason he won re-election

explanation:

"despite progress in the war, lincoln and most political pundits were convinced that he would lose his bid for reelection in 1864. the country was war weary and the democratic party's nominee, george mcclellan, was likely to negotiate a peace treaty with the confederacy if elected." - loc.gov

your mothers brothers brother in law would be your father.