More than 200 scientists have completed a twoyear study to identify the most natural and undeveloped areas on Earth. Their findings are reported in a new book called Wilderness:Earth's Last Wild Places. The book describes 37 wilderness areas around the world. Each has an area greater than 10,000 square kilometers. The study considered only areas where at least 70% of all plants are native. North and South America are home to the largest number of wilderness areas. There are 16 such areas, from southern Argentina to Alaska and northern Canada. Africa has 8 wilderness areas, including the thick forests and the grasslands. Australia and New Guinea   share 6 areas. Europe has 3 areas and Asia has 2.The Arabian Desert and Antarctica also are considered wilderness areas. The largest wilderness area is the Boreal Forest  .It extends for 16million square kilometers south of the Arctic Circle. The Boreal Forest extends across Alaska, Canada, northern Europe and Russia. The smallest of the 37 wilderness areas is the Sundarbans. It is the world's largest tidal mangrove forest  .It covers 10,000 square kilometers of land at the mouth of the Ganges River in India and Bangladesh  . The study found that wilderness areas cover about 46% of the Earth's land surface. However, they are home to less than 2.5% of the world's population. Nineteen of the wilderness areas have only about one person for each square kilometer. Native people usually live in these areas. Wilderness areas help to influence the world's weather systems and rainfall. They are also home to many plants and animals. Population growth and the spread of agriculture and mining operations threaten wilderness areas. But just 7% of all such areas have some form of official protection. The writer describes the wilderness areas to show that they    _   .
are worth the public support can attract readers' attention need to be stressed as resources are seen on every continent