HEY, IVE GOTTEN THIS FROM ENCARTA 2005!!:

World’s Longest Rivers

World's Longest Rivers                                                       Approximate  Length
Nile, Africa                                                                              6695 km/4160 mi
Amazon, South America                                                       6400 km/4000 mi
Yangtze, Asia                                                                          6300 km/3900 mi
Mississippi-Missouri-Red Rock, North America             5970 km/3710 mi
Yenisey-Angara, Asia                                                            5550 km/3450 mi
Huang He (Yellow River), Asia                                           5464 km/3395 mi
Ob'-Irtysh, Asia                                                                        5410 km/3362 mi
Río Paraná-Rio Grande, South America                           4500 km/2800 mi
Amur-Shilka, Asia                                                                  4416 km/2744 mi
Lena, Asia                                                                                4400 km/2700 mi
Congo, Africa                                                                            4374 km/2718 mi
Mackenzie-Peace-Finlay, North America                            4241 km/2635 mi
Mekong, Asia                                                                            4200 km/2610 mi
Niger, Africa                                                                              4180 km/2600 mi

Advantages: the advantages are you can make furniture out of the wood from the trees such as plywood for wooden benches. Also you can burn the wood for fire. And one more thing you can make the wood into paper to write on. disadvantages: the disadvantages are * the rainforest is being destroyed. * when it rains the trees soak up the water and prevent flooding * trees produce oxygen by taking in carbon dioxide if we cut these down we will have less oxygen which will cause further difficulties. * Deforetration will take place What is deforestration? Deforestation is the permanent destruction of indigenous forests and woodlands. The term does not include the removal of industrial forests such as plantations of gums or pines. Deforestation has resulted in the reduction of indigenous forests to four-fifths of their pre-agricultural area. Indigenous forests now cover 21% of the earth's land surface. CONSEQUENCES OF DEFORESTATION * Alteration of local and global climates through disruption of: a) The carbon cycle. Forests act as a major carbon store because carbon dioxide (CO2) is taken up from the atmosphere and used to produce the carbohydrates, fats, and proteins that make up the tree. When forests are cleared, and the trees are either burnt or rot, this carbon is released as CO2. This leads to an increase in the atmospheric CO2 concentration. CO2 is the major contributor to the greenhouse effect. It is estimated that deforestation contributes one-third of all CO2 releases caused by people. b) The water cycle. Trees draw ground water up through their roots and release it into the atmosphere (transpiration). In Amazonia over half of all the water circulating through the region's ecosystem remains within the plants. With removal of part of the forest, the region cannot hold as much water. The effect of this could be a drier climate. * Soil erosion With the loss of a protective cover of vegetation more soil is lost. * Silting of water courses, lakes and dams This occurs as a result of soil erosion. * Extinction of species which depend on the forest for survival. Forests contain more than half of all species on our planet - as the habitat of these species is destroyed, so the number of species declines (see Enviro Facts "Biodiversity"). * Desertification The causes of desertification are complex, but deforestation is one of the contributing factors (see Enviro Facts "Desertification") Here are some things you can suprise your teachers with they are DID YOU KNOW FACTS: DID YOU KNOW? * The World Resources Institute regards deforestation as one of the world's most pressing land-use problems. * An area of forest equal to 20 football or rugby fields is lost every minute. * South Africa's climate is such that less than 0,5% of its surface area is covered with indigenous forest - great care should be taken to conserve the little we have. Destroying the forest can destroy and kill endangeered species. It also affects the habitat of lots of animals. Habitat: a place or home in which an animal is adaped to or lives. hope it helps lad i've just done this i've got level 6a in it. if you need to ask me anything else just txt me see ya! !!!!!!

Mississippi River, principal river of the United States, 2,350 miles long, is exceeded in length only by the Missouri River, 2565 miles long, chief of its numerous tributaries. The combined Missouri-Mississippi system (from the Missouri’s headwaters in the Rocky Mountains to the mouth of the Mississippi River) is approximately 3,740 miles long and ranks as the world’s third longest river system - after the Nile and the Amazon. It is important to note these fighures are approximation and will vary depending on source. Hope this helps!