Plz answer these questions for brainliest!

7.The main achievement of the Qin is the fact that it unified China, creating the first dynasty ruledby the first emperor Qin Shi Huang. Other well-known achievements is the creation of the Great Wall and a large army of Terracotta Warriors

8.The Silk Road was a network of trade routes connecting China and the Far East with the Middle East and Europe. ... Although it's been nearly 600 years since the Silk road has been used for international trade, the routes had a lasting impact on commerce, culture and history that resonates even today

9. Because with a good road system, they were able to travel on safe and straight roads to get to destinations quickly as possible. They were able to carry their baggage around the country

10. Demand refers to how much (quantity) of a product or service is desired by buyers. The quantity demanded is the amount of a product people are willing to buy at a certain price; the relationship between price and quantity demanded is known as the demand relationship. Supply represents how much the market can offer. Scarcity is the state of being scarce or in short supply and shortage. And opportunity cost is the loss of potential gain from other alternatives when one alternative is chosen.

the correct answer is d