Both primary and secondary succession begin with pioneer species that — A. change the area and make it safer from predatory organisms B. invade the area so that new organisms cannot be established C. modify the area and allow larger and more complex organisms to appear D. use up all the existing resources and prevent establishment of non-native organisms (PS its science but science wasnt an option)

Which is a possible result of higher air temperatures caused by global warming? a. increase in sea level b. freezing of polar ice caps c. rapid evaporation of water in the soil d. flooding of low-lying coastal areas

Many areas surrounding the caspian sea contain important a. rare minerals b. forestry resources c. gold and silver mines d. oil and natural gas fields

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.