Answer:opioid or opium 
Explanation:Excessive use and withdrawal of opium or opioids can cause disorders in humans.
 
        
             
        
        
        
frequency because if it was anything else it would tell if he is changing his exercises to be harder on his body
The answer is frequency
 
        
             
        
        
        
Answer:
A
Explanation:
Muscles would not have been stretched out and if one does something to fast it couldnt stretch it too fast and cause strain
 
        
             
        
        
        
A bunch of nerves that are connected to your spine also connect to your brain and sends it the info we need and sends out other information throughout your body
        
             
        
        
        
Answer: In one study, exercise stimulated the human brain's ability to maintain old network connections and make new ones that are vital to cognitive health. Other studies have shown that exercise increased the size of a brain structure important to memory and learning, improving spatial memory.