Answer: The law of conservation of mass-energy applies only to nuclear reactions
Explanation: In nuclear reactions, mass and energy both are conserved but not in a simple manner.
The nuclear reactions are known to violate the law of conservation of mass because the rest mass is converted and appears in the form of kinetic energy.
But the toral energy remains the same.
Thus it can be said that the sum of mass and energy are conserved n the nuclear reactions.