I need the answers please

In shifting to a defense policy based upon the concept of "flexible response," president kennedy was indicating that he had grave doubts about thevalue of which previous defense policy? a massive retaliationb collective securityc containmentd air power

Prior to the presence of europeans on the continent, the slave trade in africa a) did not exist in any form. b) was limited to internal trade only. c) included the trans-saharan and indian ocean slave trade. d) was rarely needed due to the lack of an agricultural economy.

How did the magna carta affect the power of the english king? a) it closely linked the king's power to the power of the nobles. b) it weakened the king's power. c) it strengthened the king's power. d) it had no effect on the king's power.