The crusades were considered a turning point in history because the pope urban 2 wanted the christians to fight the muslims so that they could have back the control over the holy lands
The answer is letter A. "<span>An air battle above the English Channel to prepare for an invasion of Britain"</span> It was an aerial battle as the Germans sent their air force to drop bombs on Britain. Many civilians lost their lives and various buildings were destroyed but thanks to the leadership of British Prime Minister Winston Churchill, the British people withstood the bombardment and the Royal Air Force fought back with U.S. support preventing Germany from conquering Britain.
<span>fight to defend the polis</span>
As we know....the Roman Empire was very, very successful.....but if we look closely; I believe it's quite easy to distinguish by which means the Roman Empire used to grow. Rome just loved to war aka conquest other countries...it would use its resources and force them to pay tributaries (payment to the person whom conquered them). They had an incredibly good army..their military techniques were incredibly smart..and they also had war machines; which greatly contributed to their power on the battlefield. As far as I know, Rome rarely made alliances and agreements...Christianity was after the fall of Rome.
This being said to expand and grow, it's quite obvious that the Roman Empire went on conquests and war to expand and thrive. Alas, all Empires fall...as did the might Roman Empire.
Thus, your answer.