Professor Art Carden, from Samford University in Birmingham, Ala., is able to mow his lawn, build a fence, and install a faucet all at one time. How? He does it by employing others to do this work for him. He uses the money he earns doing what he does best and hires people to do this work for him because that is what they specialize in doing. This is an example of specialization through trade. H/T Learn Liberty