Which of the following is true about core-periphery relationships? A. They cleanly divide all parts of the world in either core or periphery. B. They require that there is only one core area at a given time. C. They reflect only economic imbalances, not cultural or political ones. D. They operate on a variety of spatial scales.

In the late 1990s, brazil’s poor people protested about crowded cities land distribution mining permits industrial pollution

During metamorphic processes, increased pressure and temperature can affect the of minerals in rock. rocks subjected to very high pressure are typically than others because mineral grains are squeezed together, and the atoms are more closely packed. during metamorphic processes, water facilitates the transfer of ions between and within minerals, which can the rate at which metamorphic reactions take place. the growth of new minerals within a rock during metamorphism has been estimated to be about per million years. metamorphism is commonly associated with convergent plate boundaries, where two plates move toward each other. during contact metamorphism, a large intrusion will contain thermal energy and will cool much more slowly than a small one. metamorphosed sandstone is known as the metamorphic rock made from metamorphosed shale, was once used to make blackboards for classrooms

These issues present challenges for regional urban areas. select all that apply. -housing availability -inadequate services -pollution -reduced population -rural migration