The civil service exam question is about opposition-the watershed is (), which is equivalent to () for rice.

I am also very upset about this problem, but I must also have an explanation. I think so:

Generally speaking, although the watershed and the Tropic of Cancer are both borders, highland barley and rice are both crops. However, the watershed and the tropic of cancer are not the same thing. In a simple understanding, it can be said that the watershed is an entity, a physical object, a specific mountain range, and the Tropic of Cancer is just a line drawn on the map to distinguish it. In real life, there is no tropic of cancer on the ground, so it is an antagonistic relationship; ;

There are also highland barley and rice. Highland barley is wheat, also known as flour, and rice is rice, also known as rice. Although they are all crops, they have different attributes, so they are also antagonistic; ;

I hope my answer can help you, so cheer for the exam! !