Wow cool bro ima just type this so I can ask a question of my own :))
        
             
        
        
        
Answer:  Energy released in the electron transport chain is captured as a proton gradient, which powers production of ATP by a membrane protein called ATP synthase.
Explanation:
 
        
                    
             
        
        
        
Answer:
13
Explanation:
it get recycled again when it becomes old
 
        
             
        
        
        
The alveoli are surrounded by tiny blood vessels, called capillaries carrying blood to and from the heart.