<span>The correct answer is: (D) Generator
Explanation:
In wind-powered systems, the wind energy turns the blades around the rotor of a wind turbine. That rotor is connected to a generator that generates electricity. In other words, the kinectic energy of the wind is converted into electrical energy by using the generator in the wind-powered systems.</span>
What gas? Gas is an invisible form so I don't see how it would have a "defined structure".