RESPONSIBILITY SEGMENT - A significant organizational, operational, functional, or process component which has the following  (a) its manager reports to the entity's top management; (b) it is responsible for carrying out a mission, performing a line of activities or services, or producing one or a group of products; and (c) for financial reporting and cost management purposes, its resources and results of operations can be clearly distinguished, physically and operationally, from those of other segments of the entity.
A single manager is responsible for each segment.