Answer:
I'm pretty sure it is B, because of natural selection
 
        
             
        
        
        
I have only heard a few phrases for spine 
Backbone 
Vertebrae (vertebral column) 
Spinal column
        
                    
             
        
        
        
Sex differences are biological and gender differences are culturally prescribed. Sex differences refers to the difference in behavior and mental functions between male and female as a result of biological difference while gender differences refers to the differences that occur between male and female as a result of cultural factors.