Natrual variations i think 
        
                    
             
        
        
        
Because they are prokaryotic cells.
        
                    
             
        
        
        
Breast milk provides antibodies to fight diseases.   
Breast milk is produced by mammary glands in the breasts and its main function is feeding an infant. Breast milk is the primary source of nutrition for newborns. The composition of the milk includes immune-boosting white blood cells, as well as stem cells, which can help organs develop, antibodies, proteins, amino-acids, oligosaccharides, growth factors, hormones, enzymes, vitamins, minerals…
 
        
             
        
        
        
Answer:
The tail and the caudal fin are the chief locomotory organs of fish and are used for rapid swimming during which tail is lashed from side to side by "alternate contraction and relaxation" of the myomeres on the two sides of the vertebral column.
Explanation: