Answer: mass can never be created or destroyed
Explanation:
not always because sometimes some things are which are bad for u
<em>OOOOOOOOOOOF!! thats like sad</em>
It's either Jack, or Roger.
Jack is the one who kills the pigs(who symbolically represent Piggy), which later orders to kills Piggy.
But Roger is the one who drops the rock on PIggy.
But the better answer would be Jack
