i think it is 8. I might be wrong.
Answer:
Heat
Explanation:
Temperature is the average thermal energy (or heat) in a substance. Sound isn't really related, thermometers measure temperature, and chemical reactions can produce heat, but none of those are measured by temperature.
Answer:
Solar energy is a renewable free source of energy
Explanation:
It is sustainable and totally inexhaustible, unlike fossil fuels which are finite. It is also a non-polluting source of energy and it does not emit any greenhouse gases when producing electricity.