These winds are found in the middle latitudes between 30 and 60 degrees latitude

Westerlies, or prevailing westerlies.

Westerlies are prevailing winds from west to east that are found in the middle latitudes between 30 and 60 degrees latitude. These winds are stronger in the winter hemisphere and times when the pressure is lower over the poles, while they are weaker in the summer hemisphere and when pressures are higher over the poles.

The westerlies are important in carrying the warm, equatorial waters and winds to the western coasts of continents.

trade regulation is a field of law, often bracketed with antitrust (as in the phrase “antitrust and trade regulation law”), including government regulation of unfair methods of competition and unfair or deceptive business acts or practices. antitrust law is often considered a subset of trade regulation law. franchise and distribution law, consumer protection law, and advertising law are sometimes considered parts of trade regulation law.

in general the theory of economics says that the more open to trade a country is the better   the result for the same country and the whole economies.

in real life countries impose taxes, quotas, etc which is not so good for the economies.

this kind of commercial war between the usa and china is slowing down the growth of the whole world so we can say that it is a draw back of trade regulations. and the free trade agreements are benefits of trade regulations.

answer; i believe the correct answer is (crops);