Humans are invented so many things in there's  history, but some invention are always precious 

That is changed humans history on the world.
We use that in our daily lives. But we didn't think much about it. Let's see whats that, 

1. Papers 


2. The Wheel 


3. Communication 


4. Medicine 


5. Electricity 


What you think?  Which one is changed human life too effectively?