Electromagnets can easily be turned on and off.
Explanation:
An electromagnet produces magnetic field which is done by the electric current. These electromagnets contain a wire would like a coil. The current passes through the wire and the magnetic field is concentrated in the center which is the "center of the coil". 
When the current is "turned off" the magnetic field "disappears". This shows that we have can have a control over the passage of current or the magnetic field. Thus, the "main advantage" of the electromagnet is that it can be easily turned on and off whenever necessary.
 
        
                    
             
        
        
        
Answer:
Active heating captures sunlight, either as heat or electricity, to augment heating systems, while passive heating captures heat from the sun as it comes into your home through windows, roofs and walls to heat objects in your home (hope that helped?)
Explanation:
 
        
             
        
        
        
Answer:
CORRECTION C.) EXCRETION
////B.) Digestion is the correct answer
 
        
                    
             
        
        
        
Alligators,crocodiles,caimans and lizards