The right answers are : Radiant energy and Conservation of energy.
Radiant energy, or radiative energy, is the only energy that can propagate in a vacuum, in the absence of matter. It is based on the principle of electromagnetic radiation, itself based on photon displacement. On a daily basis, radiant energy is very present; this is how the sun illuminates us.
-The energy of an isolated system can not be destroyed or created .
➥The energy is conserved, and can be transferred from one part of the system to another and / or change shape (heat, speed ...) .
➥Energy can also switch from one system to another.