Answer:
Respiratory system and circulatory system. 
The respiratory system allow living things to obtain oxygen from the air while the circulatory system allows oxygen to be carried around the body. 
 
        
             
        
        
        
Answer:
the food class in diagram 6 is fat or lipids
hope it helps
 
        
                    
             
        
        
        
Answer:
descending tracts is the correct answer. 
Explanation:
 
        
             
        
        
        
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Answer:
I’m pretty sure it’s all of the above! 
Explanation: