Final answer:
The common role shared by all customer and partner roles in business is shared responsibility and risk, where partners may use their complementary skills for management and are capable of making business decisions.
Step-by-step explanation:
In the realm of business, all customer and partner roles include a common role that is essential for smooth operations and mutual benefit. This common role is characterized by the shared responsibility and risk between the parties involved in the business. It's understood that partners may have complementary skills, which they use to enhance the management of the business and decision-making processes. In a partnership, each partner can potentially make all business decisions, although this is typically governed by the partnership agreement that outlines the extent of each partner's decision-making powers.