# Supply Chain

In commerce, a supply chain is a system of organizations, people, activities, information, and resources involved in
supplying a product or service to a consumer. Supply chain activities involve the transformation of natural resources, raw materials, and components into a finished product and deliver to the end customer. In sophisticated supply chain systems, used products may re-enter the supply chain at any point where residual value is recyclable. Supply chains link value chains. Suppliers in a supply chain are often ranked by "tier", first-tier suppliers being those who supply direct to the client business, second-tier being suppliers to the first tier, etc.