What are challenges for growing crops

shanghai

explanation:

after fierce fighting, the chinese armies were driven out of the shanghai area by the middle of november 1937. nanking (nanjing), the nationalist capital, fell in mid-december 1937, and the liquidation of that city and its inhabitants became known as the nanjing massacre.

mark brainliest!

answer; ///i believe the correct answer is (a) decrease biodiversity;