*select the best match from the examples

• hydrogen 

• wind power 

• bioenergy 

• hydropower 

• geothermal 

• Solar

Example

1. the most abundant element on Earth, so it is practically an inexhaustible supply and is a major candidate to replace fossil fuels.

       2. heat from the earth

       3. most used renewable energy source for electricity in the United States

       4. the most widely used renewable energy source around the world

       5. takes advantage of the fact that certain materials will produce an electric current when exposed to light

       6. generates the smallest amount of energy when considering the sources listed.