I believe that it relates to or involves free oxygen, if it is used in exercise- aerobic practices help improve the the efficiency of the body's cardiovascular system with absorbing and transporting oxygen.
Hope this helps
        
                    
             
        
        
        
A. Self-monitoring
I hope this helps your studies!
        
                    
             
        
        
        
Answer:
If you're descending the trail, step aside and give space to the people climbing up. 
 
        
             
        
        
        
Without knowing the answer choices i think his waist is normal but the BMI should most likely be examined.