What is the energy output?
sound
What is the energy output?
light and heat
What is the energy output?
heat
What is the energy output?
sound
What is the energy output?
light
What is the source of energy?
Wind
What is the source of energy?
Sun
What is the source of energy?
Electricity
What is the source of energy?
food
What is the source of energy?
People
What is the source of energy?
Gasoline
What is the energy output?
heat
What is the source of energy?
battery
What is the energy output?
Light