How do brazil's rivers contribute to its wealth?

1. The ability to transport things by the river system. For example, for power plants, it is much cheaper to use a barge to transport a load of coal than using trucks to haul it. Also the river is like a huge highway system that people don't need to maintain (road reconstruction) and goods can be shipped directly from ports a hundred miles inland out to see to the ocean where they can go around the world. 
2. Source of resources, ranging from any different species of fish to aquatic plants to fertile river sediments. 
3. Large and widespread source for irrigation of farms and orchards. 
4. Most power plants and factories are built near rivers since they use large amounts of water to produce electricity and many consumer goods. This usually effects the quality of the resources obtained from the river, but they are both still options.

Mantle convection is the process that drives plate tectonics. the theory of plate tectonics states that the crust is divided into plates that float on the semi molten mantle below. the circular motion of the magma as it slowly rises and falls or move though convection cells drags the plates along causing them to move. the heat source in the lamp would represent the earth's core. the core is the source of energy that drives convection in the mantle. the lava represents molten magma under the earth's surface. if the lava lamp had floating pieces they would move as the circular motion of the lava in the lamp as it rises and falls would move them along the surface. these floating pieces would represent pieces of the earth's crust. 

Nation of conflicting ethnic groups