A tariff is a tax imposed on products and services; this is used to control trade and one of its major disadvantages is that they rise the prices of imports giving way to a decrease in consumer surplus. What´s more, a tariff discourage competition making local industries less efficient, leading to decreases in product quality. Moreover, high tariffs may result in trade wars between nations due to the fact, exporting countries counter with their own tariffs on imported products.
The Silk Road was important because it helped to generate trade and commerce between a number of different kingdoms and empires. Now and days we would have our ingredients to make thing from them like spices from India or tea from china.
Eli Whitney is the one who invented interchangeable parts.<span />