Here were the choices on that question: 
a. poverty
b. lack of adequate rivers
c. mountains
<span>d. richness
The answer is D. richness.  Based on A Companion to World History, the African Sahel can be a corridor of communication between Nile and Niger valleys but did not materialize. The reason was the richness of Sahel that it that it can provide for itself even without trade. 
</span>
        
             
        
        
        
Iron rich minerals in rock pointed in one direction the switch to the exact opposite direction. I'd say that what supports this idea is that <span><u>Earth's magnetic field goes through pole reversals.</u></span>
        
                    
             
        
        
        
Answer:
the rate is 7 but it will not heat up better than what it did before
Explanation:
 
        
             
        
        
        
JAJAJAJ no me gustan los koreanos pero el país que más predomina petróleo es Venezuela “El petróleo cumple una triple función en la sociedad: fuente de energía, materia prima y fuente de ingresos.”
        
             
        
        
        
I think the two sources would be drip irrigation which is like a river, lake, groundwater, etc... The second source could be is making a new irragation system that could deliver water faster.