The French Naval support at Yorktown prevented the British from reinforcing and/or evacuating their troops, forcing their surrender.
I'm just quoting from a website
"the factors leading to the downfall of empires of Ghana, Mali, and Songhai
Climate change and struggles with Berber groups in the Sahara led to the downfall of the Ghanaian Kingdom
Later kings followed the patrilineal tradition, where the eldest son succeeds the father. Since there seems to have been no strict tradition, there were many fights over succession. This led to civil wars and was a large part of the reason why the Mali Empire declined.
Like the Mali Empire, the Songhai Empire also suffered from many battles over succession. In Songhai, the brothers of the king often tried to depose him; in turn, some kings tried to protect themselves by killing all their brothers. The last great battle for succession occurred when a great army general challenged a new king. Many men were killed in the battle for control of the country and the Songhai army was weakened. When troops from Morocco invaded to seize control of and revive the trans-Saharan trade in gold, the Songhai Empire could not win and was conquered, making this the last of the great West African empires."
Answer:
Urban II's movement took its first public shape at the Council of Piacenza, where, in March 1095, Urban II received an ambassador from the Byzantine Emperor Alexios I Komnenos asking for help against the Muslim Seljuk Turks who had taken over most of formerly Byzantine Anatolia.
Muhammad left Mecca to live in Medina because <span>he feared for his life. </span>The answer to your question is B. I hope that this is the answer that you were looking for and it has helped you.
I can't help you with your second question but heres a site that I've found to help you with your 1st one. I hope this helps^-^
https://nationalinterest.org/feature/5-big-lessons-the-first-gulf-war-13536