Which expression is equivalent 3/8(6+2r)+3/4x

Scientist believe that earths core is around 6000°c where does this heat come from

Say whether each of the following statements relates to the influence on weathering by rock composition, rock properties, or climate. 1.exposed rock in the mountains of alaska 2.a lack of fractures in an outcrop3.quartz is rarely affected by dissolution, hydrolysis, or oxidation4.high porosity (a large amount of space between grains in a rock)5.rocks on the coast of a tropical island6.minerals that dissolve in the presence of waterthe good earth/chapter 9: weathering and soils weathering ratesthe good earth/chapter 9: weathering and soilscompositional control1.weathering is faster in rocks composed of weaker material or material that is easily converted to weaker material (such as feldspars)2.weathering is faster in rocks made up of minerals that dissolve in water (salt, gypsum)3.weathering is slower in rocks made of resistant materials (quartz)rock property control1.weathering is faster in rocks that allow air and water in (porous, fractured)2.fractures are natural weathering surfaces3.igneous and metamorphic rocks generally have low porosity –do you think they are particularly susceptible to weathering

What was istanbul called before he ottomans conquered the city in the 15th century