Which factor of production includes human effort and time?

The correct answer is labor because it refers specifically to the human effort—both physical and mental—put into the production process. Labor encompasses the time and skills that workers contribute to create goods and services. This factor of production is crucial as it combines with capital, land, and enterprise to produce economic output.

In contrast, capital refers to the tools, equipment, and facilities used in the production of goods and services but does not represent human effort. Enterprise involves the entrepreneurial skills of individuals who manage, organize, and assume the risks of starting and running a business, but again, it does not directly involve the human effort itself. Land pertains to the natural resources and space used in production but similarly does not encompass human contributions in terms of effort and time. Thus, labor is distinctly recognized for its direct association with human effort and the time invested in production activities.