Read the passage below and choose one correct answer for each question.
Global warming and cooling have occurred naturally throughout history. But in the last 200 years, humans’ uses of fossil fuels and clear cutting of forests have increased the amount of carbon dioxide and other gases in the atmosphere. These gases trap some of the radiation from the sun which then increases the Earth’s temperature. Given the current state of environmental pollution caused by human activities, scientists believe the average temperature of the earth may increase 1-2 degrees Celsius which put simply, means some places will get much hotter and some much colder. At the same time, this overall warming effect means more frequent and more intense weather systems, especially in terms of flooding and drought.
Viet Nam is one of the most vulnerable environments due to its location on the planet. It is already subject to some of the earth’s most powerful weather systems and the increased frequency and intensity of storms will affect it often and directly, especially in coastal areas where most people live. Various estimates have been made as to the possible impacts. The most directly affected sector will be agriculture, which is very sensitive to flooding and the effects of extreme weather.
Viet Nam has the advantage of coming relatively late into the industrialization, urbanization, and modernization process. This means it can avoid many of the mistakes made by wealthier industrial countries. For example, wireless communication networks can be built from the start rather than installing lines that can easily be destroyed in extreme weather. Cities can be designed and located in less vulnerable locations. Climate-friendly building codes and standards can be created that are both more efficient and less prone to heat stress, wind damage, and flooding. Climate friendly transport systems, especially public transport, can be adopted.
The vast, humid expanse of the delta is home to more than 17 million people, who (4)_______ for generations on its thousands of river arteries.
A. rely
B. relies
C. has relied
D. have relied
