When global warming finally came, it stuck with a vengeance (异乎寻常的). In some regions, temperatures rose several degrees in less than a century Sea levels shot up nearly 400 feet flooding coastal settlements and forcing people to migrate inland. Deserts spread throughout the world as vegetation shifted drastically in North America, Europe and Asia. After driving many of the animals around them to near extinction, people were forced to abandon their old way of life for a radically new survival strategy that resulted in widespread starvation and disease. The adaptation was farming: the global-warming crisis that gave rise to it happened more than 10,000 years ago.As environmentalists convene in Rio de Janeiro this week to ponder the global climate of the future, earth scientists are in the midst of a revolution in understanding how climate has changed in the past-and how those changes have transformed human existence. Researchers have begun to piece together an illuminating picture of the powerful geological and astronomical forces that have combined to change the planes environment from hot to cold, wet to dry and back again over a time period stretching back hundreds of millions of years.Most important scientists are beginning to realize that the climatic changes have had a major impact on the evolution of the human species. New research now suggests that climate shifts have played a key role in nearly every significant turning point in human evolution: from the dawn of primates (灵长目动物) some 65 million years ago to human ancestors rising up to walk on two legs from the huge expansion of the human brain to the rise of agriculture. Indeed, the human history has not been merely touched by global climate change, some scientists argue, it has in some instances been driven by it.The new research has profound implications for the environment summit in Rio. Among other things, the findings demonstrate that dramatic climate change is nothing new for planet Earth. The benign(宜人的) global environment that has existed over the past 10,000 years—during which agriculture writing, cities and most other features of civilization appeared—is a mere bright spot in a much larger pattern of widely varying climate over the ages. In fact, the pattern of climate change in the past reveals that Earth’s climate will almost certainly go through dramatic changes in the future—even without the influence of human activity.41. Farming emerged as a survival strategy because man had been obliged（ ）.42. Earth scientists have come to understand that climate（ ）.43. Scientists believe that human evolution（ ）.44. Evidence of past climatic changes indicates that（ ）.45. The message the author wishes to convey in the passage is that（ ）.
根据现阶段的推测，艾滋病现金比较公认的来源是（）动物。
A、灵长目
B、食肉目
C、啮齿目
D、单孔目
一个英美科研小组说，我们最古老的祖先与恐龙同一时代，根据该小组的计算，现有灵长目动物(包括人)的最后的共同祖先出现于8150万年前的白垩纪。这一看法打乱了一个已经充满争论的研究领域。根据分子系统发育理论(这一理论可以通过基因突变率确定两个物种分化的时间)计算，灵长目动物从动物中分化出来的时间为9000万年前。而以经过鉴定的化石为依据的古生物学者则认为，这个时间大约为5500万年前。下列叙述符合文意的是（）。
A．灵长目动物(包括人)的最早的共同祖先出现于8150万年前的白垩纪
B．人类最古老的祖先与恐龙是同一时间出现在地球上的
C．这一观点的提出是以有关数字的计算为基础的
D．这一观点使有关灵长目动物的起源的研究充满了争议