In order to maximize land use in China for growing crops, they use which allows them to cut into the mountains and create stair step strips of land for farming.

answer; i believe the answer is (25%)plz check first good luck;

the only other powers were germany russia and uk and they were too busy fighting each other wearing each other down   that the us was becoming strong and they were becoming weaker

a and b because with the other three, they simplify to something else.