The u. s. got involved in this caribbean island nations politics to try and keep an socialist leader from power.

Explanation:

The US-Cuba relations deteriorated after the Cuban Revolution of 1959 and US severed diplomatic ties with Cuba in 1961 began operations to topple the Cuban government and also imposed restrictions against it as Cuban government had nationalised US corporations property in Cuba. Pigs of Bay invasion(1961) was a major step taken by US government to stop Fidel Castro's attempt to spread communism throughout Latin Africa and America.

describe a little more.

the conditions that made the byzantine empire vulnerable to attacks by the muslin turks were the sack of constantinople by western crusaders, the conquests of the sultanate of rum, presence of rival kingdoms and finally the set up of fiefdoms at the empire which were owned by the ghazis (turkish warriors).