The immediate effect of the Plessy v. Ferguson decision was that Segregation in public became "separate but equal." This just means that the standards for the segregation law remains and was not totally eliminated but the decision considered the equal rights of citizen for a humane and dignified living.
Desertification has affected parts of Africa as:
D. it has led to a decrease in land available for farming.
Explanation:
Africa has the biggest desert in the world : the Sahara which is ever expanding and there are other lands in the semi arid regions near the sub tropic too.
This is because of a combination of the geographic features of the sub arid regions, the less nutrient soil that is prone to desertification and the fact that the wind currents are aversion for constant precipitation.
This means that there is increasingly less farm land in the continent.