Cellular respiration results in decreased biomass for a plant. <span>In cellular respiration glucose and oxygen yield
water and carbon dioxide. So, carbon dioxide is released in the into the air instead of forming organic molecules which could increase the biomass.</span>
        
             
        
        
        
prevents backflow into the left atrium 
 
        
             
        
        
        
Because since their ancestors came before them then they inherit certain beneficial traits that help them survive. Those traits are in the DNA and the animals are evolving to be more fit for the environment that they are in. (hope this helps)
        
             
        
        
        
CENTRAL NERVOUS SYSTEM INCLUDES THE BRAIN AND SPINAL CORD.