Many things that we use every day, like televisions, computers, refrigerators, and microwaves, require energy in order to work. We also rely on energy to make a car run and to heat water. All of the energy that we need to use must first be produced. Some sources of energy, such as gas and oil, can be harmful to the environment. Burning gas and oil can pollute the air. Also, gas and oil are limited, and we are using up the small amount that is left on the planet. This is why people should use alternative energy sources, which do not pollute the environment and are plentiful. Solar and wind energy are clean energy sources that should be used more often to reduce the pollution on Earth. What text structure is it?

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sequence
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classification
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definition
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problem and solution