The questions in this group are based on the content of a passage. After reading the passage, choose the best answer to each question. Answer all questions following the passage on the basis of what is stated or implied in the passage. Since the 1970s, a multitude of scientists from the fields of climatology, oceanography, and biology have been warning the governments of the world that unless human societies reduce their emissions of 'greenhouse gases'--gases such as carbon dioxide and methane that increase the capacity of the atmosphere to retain heat--world-wide global warming caused by these gases will result in catastrophic consequences for people and the environment. In December 1997, a group of delegates from over 100 nations gathered together in Kyoto, Japan, in order to work out the details of the Kyoto Protocol to the United Nations Framework Convention on Climate Change, the most comprehensive international effort to date to combat the rise of greenhouse gas emissions. The chief goal of the Kyoto Protocol is for industrialized nations to reduce their emissions of green-house gases by 5.2 percent compared to 1990 levels. The gases targeted by the protocol are carbon dioxide, methane, nitrous oxide, sulfur hexafluoride, HFCs, and PFCs. The protocol contains some provisions for developing nations, but as the per-capita emissions of greenhouse gases from these nations are much lower than those of industrialized nations, the majority of the reductions called for by the protocol come from the European Union (8 percent reduction from 1990 levels), the United States (7 percent reduction), and Japan (6 percent reduction). Proponents of the Kyoto Protocol maintain that although it is not sufficient by itself to halt global warming, it represents an important first step toward a sustainable global economy. These proponents argue that most of the reductions in green-house gases can be achieved through improvements in efficiency and the use of cleaner fuels. While they concede that the provisions of the protocol may slow economic growth in affected nations, they maintain that the potential economic costs are far outweighed by the benefits of avoiding the ravages of global warming, which they say could include rising sea levels, erratic weather patterns, and long-term reductions in biodiversity. Critics of the Kyoto Protocol argue that it is unnecessary, unfair, and too costly to implement. It is unnecessary, they maintain, because the scientific community is still divided on the questions of whether global warming is happening and, if it is, whether human activity is the cause. They say it is unfair because the provisions primarily limit the emissions growth of industrialized nations while giving free rein to developing nations such as India, which actually emit more greenhouse gases than many industrialized nations, and that this situation will give the developing nations an economic edge in the global marketplace. Furthermore, they argue, the costs of switching fuels and limiting energy use will severely damage the economy, and the negative effects of this economic depression will outweigh any theoretical gains to be had by delaying global warming. Which of the following best describes the structure of the passage?