The crossing over mechanism of genetic variation results from the exchange of gene segments between non sister chromatids. The correct answer is A. 
        
                    
             
        
        
        
Answer:
Explanation:
Self-pollination occurs when the pollen from the anther is deposited on the stigma of the same flower, or another flower on the same plant. 
 
        
             
        
        
        
Explanation:
Fueron identificados por un estudio de un grupo de investigadores en Israel y su análisis indica que el Homosapiens  ya vivía fuera de África hace 185.000 años, unos 80.000 años antes de lo que se pensaba.
 
        
             
        
        
        
Explanation:
Gene expression is the process by which the instructions in our DNA are converted into a functional product, such as a protein.