Which of the following statements describes a challenge that agriculture faces in the coming decade?
a. reliance on farm mechanization will need to be limited
b. farmers in africa must adopt new methods to meet their agricultural needs.
c. farm businesses will need to increase their wages to attract more labor
d. for production will need to be reduced to conserve the diminishing supply of fertilizers
2. which of the following statements about ethnic and religious conflict in africa is false?
a. african nations typically have peaceful transitions of power, but leaders have been unable to quell ethnic violence
b. states created during european colonization had tremendous religious and ethnic diversity
c. ethnic conflict has led to he oxide in some cases
d. european borders gave little respect to traditional tribal and ethnic boundaries

Scientist: cross-sections of stalactites—calcite formations deposited on cave ceilings by seeping water—can reveal annual variations in rainfall in particular areas over hundreds and thousands of years. we often found that when—according to these cross-sections—drought occurred in a particular area, it coincided with the collapse of an ancient society in that area. i hypothesize that drought reduced agricultural productivity in these areas, thereby leaving these societies without the resources needed to handle internal stresses and external threats. which of the following, if true, would most weaken the support for the scientist's hypothesis? a. many droughts indicated in the cross-sections of stalactites do not correspond with the collapse of a society in that area. b. information from the cross-sections of stalactites alone cannot reveal the level of agricultural output in an area at a particular time. c. most of the societies that collapsed during droughts did so when internal power struggles coincided with military raids from neighboring societies. d. most of the societies that collapsed during droughts maintained large stockpiles of food and water at the time of their collapse. e. information from stalactites also suggests that the collapse of some societies coincided with periods of abnormally high rainfall.