Answer:
The total amount of both matter and energy remains the same
Explanation:
The matter is defined as anything that has some weight and it occupies some volume.
On the other hand, energy is defined as the capacity/ability to do work.
According to the law of conservation, it says that energy can neither be created nor destroyed, but it transforms from one kind to another.
Also according to Einstein's mass-energy equation, it says that matter that is comprised of certain energy is equal to the product of their mass and square of its light speed.
Thus, in a closed system, both matter and energy can change its forms but their total amount remains the same.
