Climate change is one of the most important environmental issues facing humankind. Understanding the potential impacts of climate change for natural ecosystems is essential if we are going to manage our environment to minimize the negative consequences of climate change and maximize the opportunities that it may offer. Because natural ecosystems are complex, nonlinear systems, it follows that their responses to climate change are likely to be complex. Climate change may affect natural ecosystems in a variety of ways. In the short term, climate change can alter the mix of plant species in land ecosystems such as grasslands. In the long term, climate change has the potential to dramatically alter the geographic distribution of major vegetation types--savannas, forests, and tundra. Climate change can also potentially alter global ecosystem processes, including the cycling of carbon, nitrogen, phosphorus, and sulfur. Moreover, changes in these ecosystem processes can affect and be affected by changes in the plant species of the ecosystem and vegetation type. All of the climate change-induced alterations of natural ecosystems affect the services that these ecosystems provide to humans.
The global average surface temperature increase of half a degree Celsius observed over the past century has been in part due to differential changes in daily maximum and minimum temperatures, resulting in a narrowing of the diurnal temperature range. Decreases in the diurnal temperature range were first identified in the United States, where large-area trends showed that maximum temperatures have remained constant or increased only slightly, whereas minimum temperature have increased at a faster rate. In this issue, Alward et al. report on the different sensitivities of rangeland plants to minimum temperatures increases.
Which of the following is NOT mentioned as a reason for the global warming?
A.The burning of fuels such as coal or oil.
B.The clearing of forests.
C.The cultivation of farmland.
D.The negative consequences of human activities.
第1题
阅读以下说明,回答问题1、问题2、问题3、问题4和问题5,将解答填入对应栏内。
[说明]
某单位要拟建一个小型局域网,其图如9-1所示,PCI、PC3、PC5的IP地址分别为10.191.140.2, 10.191.140.3,10.191.140.4,子网掩码是255.255.255.0。PC2、PC4的IP地址分别为10.191.139.2,10.191.139.3,子网掩码是255.255.255.0。
请说出图9-1的拓扑结构名称与特点。
第2题
阅读下面的说明,回答问题1~问题4,将解答填入答题纸对应的解答栏内。
[说明]
阅读以下说明,回答问题1~问题4,将解答填入答题纸对应的解答栏内。
windows Server 2003是一个多任务多用户的操作系统,能够以集中或分布的方式实现各种应用服务器角色,是目前应用比较广的操作系统之一。
Windows内置许多应用服务功能,将下表中(1)~(5)处空缺的服务器名称填写在答题纸对应的解答栏内。
(1)
第3题
第4题
阅读下列说明,回答问题1至问题2,将解答填入对应栏内。
【说明】
利用Windows Server 2008架设邮件服务器,回答相应问题。
邮件服务器通常提供POP3和SMTP两种服务,它们各有什么作用?
第5题
阅读下列说明,回答问题1至问题3,将解答填入对应栏内。 【说明】 某银行的转账业务分为如下两类操作: ()
第6题
阅读以下说明,回答问题1、问题2、问题3和问题4,将解答填入对应栏内。
[说明]
lis(Internet Information Server)是网络信息服务器,它应用于Windows 2000/XP,IIS服务器的优点是有可视化的界面,安装、管理比较方便。在Windows 2000 Server中配置界面如图13-3所示。Web站点IP地址为10.191.140.100,网站网页所在的起始目录为“H:\CIU\MYROOT"。
根据题中所给信息请把图13-3中的(1)与(2)填写完整。
第7题
阅读以下说明,回答问题1和问题2,将解答填入对应栏内。
【说明】
在信息系统工程监理中,由于各方面的原因,对于监理单位而言,也是存在风险的。
监理工作的风险有哪些?
第8题
阅读下列说明,回答问题1至问题2,将解答填入答题纸的对应栏内。
[说明]
电子商务系统的外部社会环境如图10-5所示。
请把空缺的地方填写完整。
第9题
阅读以下说明,回答问题1、问题2、问题3、问题4和问题5,将解答填入对应栏内。
[说明]
Cable Modem可以作为一个网桥直接与用户相连,也可以作为一个路由器与Hub相连,从经济角度考虑,目前采用后一种方式居多。有一种HFC网络如图6-2所示,要以楼层为单位安装Cable Modem,通过智能Hub接入8~16个用户,提供Internet接入、视频点播、音频点播、IP电话、个人主页、E-mail、远程教育和远程医疗等网上服务。
请分别说出(1)与(2)的设备名称。
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