A fat free diet is dangerous because IT CAN RESULT IN DEFICIENCY OF ESSENTIAL FATTY ACIDS. 
Essential fatty acids refers to those fatty acids that humans must eat in their foods because the body can not synthesize them and they are required for good health. There are three type of essential fatty acids, these are arachidonic, linoleic and linolenic acids. When these essential fatty acid are absent in one's diet they lead to ill health. 
        
                    
             
        
        
        
Artificial Selection or “ Selective Breeding”. aka the process by which humans use animal breeding and plant breeding to selectively
        
             
        
        
        
Female. If the puppy has two identical chromosomes, it would be XX, being female. 
        
                    
             
        
        
        
Not applicable ): in all situations