I'm pretty sure that you are talking about mass.
        
                    
             
        
        
        
The skin will get infected
        
             
        
        
        
The overall function of the digestive system as digestion and absorption of food stuffs, and the general activities of each digestive system organ is; Ingest, digest, absorb, defecate. 
Ingestion involves placing food into the mouth, propulsion involves propelling food from one organ to the next using peristalsis. Mechanical digestion involves the physical fragmenting food into smaller particles. Chemical digestion refers to breaking down food molecules to building blocks by enzymes. Absorption is the transport of digested end products to blood or lymph; and finally Defecation which involves the elimination of indigestable material from GI tract by anus. 
        
             
        
        
        
Shrubs and trees regrow quickly in an area that has been burned during a forest fire.
Algae,grasses, and other small plants grow on newly exposed rock over a long period of time.
        
             
        
        
        
The answer is called photosynthesis. Hope this helps.