Question

garbage causes pollution.it may be used as a source of energy.joining into relative clause

Answer 1

Garbage which causes pollution may be used as a source of energy

Answer 2

In the environmental law of the United States, relationships between state and federal parties often shape environmental laws and the practical impact of those laws. In addition, environmental problems often do not have well defined boundaries and thus jurisdictional overlap complicate these matters. These complications bring into question how environmental laws are created, how these laws should be enforced, and whether the state or federal government should have the final word in specific environmental debates.