The answer is, different versions of the same gene are called alleles
        
             
        
        
        
It is extremely useful for geologists, because most specimens of a given mineral are very close to the same hardness. ... So, we can conclude that not all the rocks are hard, and the hardness of rocks depends on how the atoms of the rock's minerals are bound to each other and how they are arranged.
        
             
        
        
        
from the way it was created 
 
        
             
        
        
        
The correct answer is choice B. Nondisjunction.
Nondisjunction disorder occurs when either the homologous chromosomes or the sister chromatids fail to disconnect properly during cell division. This failure results in daughter cells with an abnormality in chromosomes. 
I hope this helps you and have an awesome day!! :)