Answer:
the tendency toward a relatively stable equilibrium between interdependent elements, especially as maintained by physiological processes.
Explanation:
 
        
             
        
        
        
Answer: At night when no light is present plants can only utilize cellular respiration so the overall net change of co2 they "consume" is pretty low but still beneficial at the rates humans seem to be dishing co2 out.
 
        
                    
             
        
        
        
Answer:
It is well supported by evidence.