It would be D) carbon dioxide (I took the test haha).
C. population
There are more representatives in the court for areas that are more densely populated so that the population/representative ratio remains comparative.
Answer: A trade barrier is a restriction on international trade.
Explanation: Trade barriers are government efforts to control/block any trades outside the country. They decrease general economic efficiency, which can be further supported by the theory of comparative advantage. Comparative advantage means that when a country produces a good for a lower opportunity cost than other areas. A country with comparative advantage makes trade-offs worth it.
Hope this helps! Let me know if you have any other questions. :)
Answer:
Which article? I will tell you the answer in the comments
