The integumentary system (skin) has been called a membrane and an organ but, it is generally considered a system because it has organs that work together as a system. It is sometimes considered an organ because it contains several types of tissues and a membrane and it covers the body.
 
        
                    
             
        
        
        
Living things obtain and use energy so alive?
        
                    
             
        
        
        
Answer:
C. Responsiveness and timing
Explanation:
I just know it, I really don't know how to explain