Answer:
Conserved
Step-by-step explanation:
Conserved energy refers to the energy the amount of energy that exist within an isolated system an remain constant. This is possible because energy cannot be destroyed. Energy can only be transformed from one form to another form or get transferred from one system to another.
When the person pushed a box, the mechanical energy that he generate from his body movement to the box caused the weighted object in front of him to move. The downward force from the weight of the box created a friction with the surface and caused the energy to be conserved heat , whch is a form of kinetic energy.