Repeated foreign invasions where a huge problem during that time period for the Chinese, so it would be D.
Answer:
Christopher Columbus introduced horses, sugar plants, and disease to the New World, while facilitating the introduction of New World commodities like sugar, tobacco, chocolate, and potatoes to the Old World. The process by which commodities, people, and diseases crossed the Atlantic is known as the Columbian Exchange.
this is from khanacademy
Explanation:
Hello there.
<span>Which of these is true of the century following the Pax Romana?
</span><span>C) The Roman military kept the empire's borders secure.</span>
Because it was strong dictator ship which is what italy and germany where being as they were allies.
