All of the following were agricultural hearths, except
a.
mesopotamia
b.
sub-saharan africa
c.
the nile river valley
d.
mesoamerica

B. sub-Saharan Africa

Explanation:

The agricultural hearths were located along the Nile River, Mesopotamia, Hindus and Ganges Rivers, Mesoamerica, which is also where the first civilizations formed. Sub-Saharan Africa though was not keeping the pace with these regions, and the people living there were either not engaging in agriculture at all, or it was on a very small scale. That has led to a much slower development of this region, stagnating for thousands of years, eventually putting in a very bad situation when it confronted with the more developed civilizations later on in the history. One of the major reasons for not developing a large scale agricultural production has been the climate, which in the majority of the region is not well suited for such activity.

b.

developed countries have tended to improve the environment, while developing countries have tended to damage it.

polar areas, such as antarctica or the south pole.