单选题 Passage Four
Severe climate change was the main driver behind the birth of civilisation, a scientist said yesterday. An increase in harsh, arid conditions across the globe around 5,000 years ago forced people to start living in stable communities around remaining water sources. "We can certainly say that the earliest civilisations arose on the backdrop of increasing dryness, which are driven by natural, global-scale changes in climate," said Nick Brooks of the University of East Anglia. "The cultural transitions track changes in environmental conditions quite closely."
Dr. Brooks said his research turned traditional ideas of how the world's first civilisations started--such as those in Egypt, China, the Indus Valley region and South America---on their head. Many anthropologists think that civilisation was spread gradually among populations after it began in some part of the world. 'A current popular theory is that the world's first civilisation developed because it could; the environment was relatively friendly," said Dr. Brooks. "This is based on the argument of the last 10,000 years being climatically very stable and quite conducive to flourishing of agriculture and large, urban civilisations."
But Dr. Brooks argued that civilisation arose instead from environmental calamities. His work is focused on the Sahara region, where he says the cultural history shows that, around 5～10,000 years ago, the humid areas there abruptly changed into the Sahara desert we see today. The Garamantian tribe, which lived in what is now south-west Libya more than 3,000 years ago, emerged when the land there dried out. After this period, we see the first stone structures, the beginnings of urbanisation, agriculture and the development of novel technologies to access ground water, such as wells," said Dr. Brooks. "What we see here is the story of people responding to the environmental change with the drying up of the region. That leads to the emergence of the Garamantian state."
He added that the stow was similar in the other cradles of civilisation around the world. Without the driving force of climate change, human societies might have evolved far more slowly, said Dr. Brooks. "Maybe we would have remained village farmers and herders, hunter-gatherers and so on," he said. "Perhaps you'd have a less population-dense kind of civilisation./

单选题 According to Nick Brooks, ______.
A. differences in civilizations are the result of differences in climate conditions
B. the emergence of civilizations is closely related to climate change
C. the development of civilizations has caused the world climate change
D. similar civilizations have appeared despite various climate conditions

单选题 The phrase "turn... on their head" (Paragraph 2) is closest in meaning to ______.
A. confirm B. extend C. challenge D. supplement

单选题 The traditional theory argues that the rise of civilizations ______.
A. benefited from a stable and good environment
B. was meant to improve the living environment
C. had little to do with the environment
D. was the result of environmental change

单选题 The Garamantian tribe is mentioned to show ______.
A. the relations between human activities and the emergence of deserts
B. the human creativity in fighting unfavorable environment conditions
C. the importance of water resources at the beginning of human civilizations
D. the effect of environmental changes on the development of human society

单选题 According to Dr. Brooks, without significant climate change, human civilizations would now be more
______.
　　　A. diverse B. predictable C. aggressive D. primitive

单选题 The purpose of the passage is to ______.
A. analyze how climate change affects civilization levels
B. question the link between climates and civilizations
C. introduce a latest study on the rise of civilizations
D. discuss how civilizations spread throughout the world