<span>the best option is B
the development of more efficient agriculture
The emergence of efficient forms of agriculture especially in Mesopotamia, led to emergence of early city states as food was produced in surplus to feed the town population. it also led to division of labor. this form of agriculture also contributed to sedentary lifestyle and improved nutrition thus explosive population that contributed to city establishments.
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Scientific racism<span> (sometimes </span>race biology<span> or </span>racial biology<span> or </span>pseudoscientific racism<span>) is the </span>pseudoscientific<span> study of techniques and hypotheses attempts to reveal the biological differences between races which can be used to support or justify belief in </span>racism<span>, racial inferiority, or </span>racial superiority;<span> alternatively, it is the practice of classifying</span><span> individuals of different </span>phenotypes<span> or </span>genotype<span> into discrete </span>races. Historically it received credence in the scientific community, but is no longer considered scientific.
Answer:
I would go with B, "populations declined in urban areas"
Explanation:
For all 3, the urban population is much greater in 100 CE than 1000 CE. I find the graphs to be set up in a poor way and you'd expect them to have grown, so forgive me if I'm wrong.