Song China's agricultural specialty crop is sugar.
Hope it helps!
Answer:
The Qing Dynasty collapsed in the early 1900s due to corruption, peasant unrest, ruler incompetence, and population growth which led to food shortages and regular famine
"They promised bills and laws in favor of immigrants in exchange for votes" is the one way among the following choices given in the question that political machines, such as Tammany Hall, work with and for immigrants.