N2015, six powers (us, united kingdom, france, china, russia, germany) negotiated a nuclear deal with iran, the joint comprehensive plan of action (jcpoa). what were the positives and negatives of this accord? why has president donald trump unilaterally withdrawn from this agreement, even though the other nations continue to accept it? how would you describe the present leadership and policies of iran in the region? what are the advantages and the costs/risks of this decision by the united states to withdraw? since then, iran is accused of attacking saudi arabian oil fields and president trump announced, then cancelled, a military response. u. s. economic sanctions are at their highest. in your view, is military conflict between the u. s. and iran likely in the near future?

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.