What factors explain the major increase in population in half of China and a much smaller change in the other half?

an invasion from the north and rich farmland to the south
an invasion from the south and rich farmland to the north
overland trade and urbanization
seagoing trade and urbanization

please need hel

they required less loading and unloading

explanation:

the shipping container improved shipping because it cut down on unloading time by three weeks, eliminated wasted space, and allowed ships to carry.

the indians crossed artificial boundaries, setting the stage for conflict

geography

this is because warmer climates often don't get people sick from the flu and regions where it was often colder more people received the flu. hope this if you need more reasoning i am here to