One advantage is that whatever resource it is, it will never run out and you wont have to worry about not having it. A second is that there is going to be enough for everyone to use however much they want without there having to be a limit on how much you use.
Answer:
Explanation:
Given
Initial Intensity of light is S
when an un-polarized light is Passed through a Polarizer then its intensity reduced to half.
When it is passed through a second Polarizer with its transmission axis 

here 


When it is passed through third Polarizer with its axis
to first but
to second thus 



When middle sheet is absent then Final Intensity will be zero
Answer: Single replacement
Explanation: A P E X