A market normally consists of (a) individuals and organizations who (b) are interested and willing to buy a particular product to obtain benefits that will satisfy a specific need or want, and who (c) have the resources (time, money) to engage in such a transaction.
With the understanding of this, some markets are sufficiently homogeneous that a company can practice undifferentiated marketing in them. That is, the company attempts to market a line of products using a single marketing program. But because people have different needs, wants, and resources, the entire population of a society is seldom a viable market for a single product or service.