It is very important to note that these five functions do not exist in isolation and treating them as isolated units within the organization is a mistake that has been made many times. There are efficiencies and cost savings to coordinating the operation and leveraging the inter-relatedness of business units.
For example, sales and marketing must advise operations of projected sales and promotions so that there are enough products to meet expected demand. Inbound logistics needs these numbers too, so that they can source enough materials, have the right number of staff, and be able to handle the incoming materials. At the same time, outbound logistics requires that they know how much product they have to be ready to deliver and to whom, and service has to know what to be ready for too.