What are the two key concepts for this section? What types of commercial energy resources do we use to supplement energy from the sun? Distinguish between nonrenewable and renewable energy resources...

What are the two key concepts for this section? What types of commercial energy resources do we use to supplement energy from the sun? Distinguish between nonrenewable and renewable energy resources and give three examples of each type. What percentage of the energy used in the world and in the United States comes from each of these types of energy resources?