NO maturity does not depend on age people that are like 20 can act childish and 12-15 can act just like adults
        
                    
             
        
        
        
"String-along songs about razor blade" were the author's narration of an advertisement on razor blades.
 
        
                    
             
        
        
        
Answer:
The book discusses various possibilities of advanced technology that can alter the brain and mind. Looking into things such as telepathy, telekinesis, consciousness, artificial intelligence, and transhumanism, the book covers a wide range of topics. In it, Kaku proposes a "spacetime theory of consciousness".
Explanation:
Hope it helps ya!!
~Mylie~