3. What is the original source of energy for all fossil fuels? hydrocarbons

photosynthesis

the Sun

cosmic radioactivity

the sun

Explanation:

All the energy in oil, gas, and coal originally came from the sun, captured through photosynthesis. In the same way that we burn wood to release energy that trees capture from the sun, we burn fossil fuels to release the energy that ancient plants captured from the sun.

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its temperature is increasing. this causes molecular vibrations to increase.