Explanation: LAW
The necessity of fighting off invading groups was one aspect of the Roman Empire that continued into the Byzantine Empire. The Byzantine Empire, a very powerful and vast civilisation, emerged after the Roman Empire during Late Antiquity and the Middle Ages. Constantinople became its capital.
The appropriate answer is b. Mongol tribes invading Muslim lands. The Mongol tribes had been empowered Genghis Khan and as such had become a formidable hoard of conquerors that had seized much of the Eurasian landmass and the ruling Islamic caliphate in the west. The hardships during this period marked the end of the Golden age of Islam. <span />
Spanish exploration of the New World was led by Christopher Columbus and Juan Ponce de Leon, who invaded and colonized great parts of what would become South, Central, and North America.
