Answer:
because of factories and cars and smoking
Explanation:
 
        
                    
             
        
        
        
Answer:
the cell membrane becomes depolarized. 
Explanation:
Na+ moves in, K+ moves out. 
hope it helps! 
 
        
                    
             
        
        
        
Answer:
A. Rheumatoid arthritis is characterized by periods of remission and exacerbation
C. Rheumatoid arthritis can cause fatigue and weight loss
Explanation:
 
        
             
        
        
        
Fetch 
(sry have to make an answer 20 characters /!:!27837)