All three options you provided—labor, electricity, and steel used in manufacturing automobiles—are considered inputs of production.
- Labor refers to the human effort used in the production of goods and services.
- Electricity is considered an input because it provides the energy necessary to operate machinery and equipment used in production.
- Steel used in manufacturing automobiles is a raw material that is transformed into a final product during the production process.
So, each of these is a valid input of production.