Final answer:
Location, distribution channels, and the link between functions are bases of differentiation that are usually difficult/costly to imitate.
Step-by-step explanation:
The bases of differentiation that are usually difficult/costly to imitate are location, distribution channels, and the link between functions. These elements can provide a competitive advantage to a firm because they are unique to the organization and can be challenging for competitors to replicate. For example, a store's prime location in a high-traffic area can attract more customers, while an efficient distribution network can ensure timely delivery. Similarly, a strong link between different functions within a company can lead to improved communication and coordination, enhancing overall operations.