C, as A,B, and D aren't true.
        
             
        
        
        
House sparrows in the northern part of North America are larger than those found in the southern regions. The possible mechanism of microevolution is more likely to be responsible for this is natural selection. The answer would be letter B.
        
                    
             
        
        
        
Explanation:
The hydrologic cycle describes the pilgrimage of water as water molecules make their way from the Earth's surface to the atmosphere, and back again. This gigantic system, powered by energy from the sun, is a continuous exchange of moisture between the oceans, the atmosphere, and the land.
 
        
             
        
        
        
Answer:
Genetic Mutation 
Explanation:
Speciation can be driven by evolution, which is a process that results in the accumulation of many small genetic changes called mutations in a population over a long period of time.
There are a number of different mechanisms that may drive speciation. 
Two of them to point out here.
1. natural selection 
2. genetic drift 
 genetic drift describes random fluctuations in allele frequencies in populations, which can eventually cause a population of organisms to be genetically distinct from its original population and result in the formation of a new species.