Read the following paragraph and answer the question. Give ONLY the answer, no other words or explanation.

For example:

Answer: <most likely answer, as short as possible>.

Paragraph: 
The Sun produces far more energy than humans can use. The Sun is also the source of most of the energy we use. Fossil fuels and wind energy, for example, originate with the Sun. So why don't we get all our energy from the Sun? For one reason, it's not always practical.


Question: What is the source of most of the energy used?
the sun
The Sun.