I believe the bone system that red marrow belongs to is D. Skeletal system.
        
                    
             
        
        
        
Reproduce through mitosis.
        
                    
             
        
        
        
C. natural selection. 
This is because in smaller populations the more that two separate groups of animals don’t interbreeding the father they become until speciation occurs where they cannot interbreed between the two groups.
 
        
                    
             
        
        
        
Epithelia are classified by the number of cell layers and the general shape of the cells