The most important reason why most farmers in northeast china grow crops other than wet rice is

Climate in Northeast China is the most important reason why most farmers grow crops other than wet rice. They experience little rainfall during summer and winters are harsher than in other areas. These types of conditions are not suitable for growing rice. Their crops are mostly oats, cotton, soybeans, tobacco and corn. 

The correct answer is:   [b]:   "has no atmosphere" .

According to new research, more than 5..5 million deaths are associated with polluted air. hope this : ).