The economy of Africa consists of the trade, industry, agriculture, and human development. Following the independence of African countries during the 20th century, economic, political and other means
        
                    
             
        
        
        
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The ranking of common igneous silicate minerals based on the temperature at which crystallization occurs is called Bowen’s reaction series.
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In  Bowen’s reaction series the minerals with high crystallization temperature are present at the top layer. This means these minerals are the first to crystallize from the magma and they are mostly unstable. The Bowen's reaction series is represented in the Y shape. The left branch of this Y has minerals containing iron and magnesium. They are called as Ferromagnesium minerals. 
The right branch of the Y contains plagioclase feldspars minerals. Temperature gradually decreases down along the Bowen’s reaction series from  to
to  . At certain low temperature, the two branches combine forming minerals similar to felsic rocks such as orthoclase feldspar, quartz and muscovite mica.
. At certain low temperature, the two branches combine forming minerals similar to felsic rocks such as orthoclase feldspar, quartz and muscovite mica.
 
        
             
        
        
        
C. the rocks closest to a continent are younger
        
             
        
        
        
Answer:
Over time people move to other places depending on their opportunities.
Explanation: If someone wanted to be a farmer they would settle down in a more fertile area where they can get more land. and someone who wants to be a lawyer or doctor would settle in a more busy area in the city.
 
        
             
        
        
        
Answer: Abrahmism religion