What are the phases shown in a and d called?

Based on this map, which statement about africa’s economic activity is most accurate? a) coastal countries are all members of opec b) economic development is more common with opec nations c) coastal countries have more access to productive resources d) economic development is more common above the sahara desert

Gemstones are commonly found in pegmatites, which are igneous rocks that are a. exceptionally mafic b. exceptionally coarse grained c. exceptionally fine grained d. extrusive, forming from lava

17. the soil erosion pictured here is the result of what? a. harvesting renewable resources at a rate greater than the sustainable yield b. a mudslide caused by excessive rains c. harvesting renewable resources at a rate lower than the sustainable yield d. the transition between geologic eras and eons