In africa, what do most people do to earn a living?
a.
work in factories
b.
mine for diamonds, gold, or other resources
c.
farm or herd, mostly at the subsistence level
d.
work in service industries, such as banking or health care

C. Farm or herd, mostly at the subsistence level

Explanation:

In African the dominant source of income is farming and rearing of animals. Moreover, most of our farming are not fully mechanize or commercialize. Our farming are mostly at the subsistence level due to various factors like lack of support from government, lack of technical-know-how etc.

Most individuals engage in farming at a subsistence level and sells parts of the produce to carter for their other needs.  

question

which are human systems?

the amazon rain forest

the appalachian trail

the george washington bridge

the himalayas

the hoover dam

the north american free trade agreement