Both earthquakes and volcanoes are a result of
the sun's energy
plate tectonics
subduction
seafloor spreading

For sure, one of the answers is Plate tectonics. The second answer would most likely be subduction, due to the fact, in the lessons revolving this question, it mentions both earthquakes and volcanoes caused by subduction.

radiative zone

explanation    

radiative zone is the layer of the sun which energy is transferred away from the core by radiation. although, the core is the only part of the sun that produces an appreciable amount of heat through fusion. in fact, 99% of the energy produced by the sun takes place within 24% of the sun's radius.