Answer:
Its A . serve as a food source for other organisms .
Explanation:
<em>h</em><em>o</em><em>p</em><em>e</em><em> </em><em>i</em><em>t</em><em> </em><em>h</em><em>e</em><em>l</em><em>p</em><em>s</em><em> </em>
 
        
                    
             
        
        
        
I want Brainliest!!!!!!!!!!!!!
 
        
                    
             
        
        
        
Answer:
Combustion
Explanation:
Combustion is the chemical reaction that happens when fuel burns.