Which of the following transforms energy from one form to another?

Energy transformation specifically refers to the process by which energy changes from one form to another. For example, when you use a toaster, electrical energy is transformed into thermal energy to toast the bread. This concept is fundamental in physics and helps illustrate how we utilize different forms of energy in various devices and systems.

In contrast, energy conservation refers to the principle that the total energy in a closed system remains constant, meaning energy is neither created nor destroyed but can only change forms. Energy transfer involves moving energy from one location to another without changing its form—such as transferring heat from a hot object to a cooler one. Energy depletion indicates a reduction in energy resources, which does not relate directly to the change of energy forms.

Therefore, energy transformation is the correct choice as it accurately describes the conversion process between different energy types.