What's this?
a windmill
What's this?
a sailboat
What's this?
a wind turbine
What's this?
a wind farm
What's this?
coal
What's this?
oil
What's this?
natural gas
What's this?
pollution
What's this?
power plant
What's this?
electricity
What's this?
a highway
How do we call this?
recycling
What kind of energy is this?
renewable energy
What are these?
fossil fuels
What are these?
sources of energy
