Yes it can kill brain cells. if you hold your breath for a short amount of time example 10 seconds it won't do any harm. but if you hold your breath for an extended time like a minute the cells will not get enough oxygen and eventually die. I hope I helped you
        
             
        
        
        
The conversion of light energy into chemical energy. (use of energy)
        
                    
             
        
        
        
This app is used world wide , maybe try asking a classmate
        
             
        
        
        
Natural world beore its use if we consider world before darwin theory, the world was occupied by various individual such as dinasours and primitive plants