What are the various components in sequence diagrams?

Answer

The Various components in sequence diagrams are:

• Actor: Actor represents an external user / end user who interact with the system.
• Object: Object is represented by one of components of the system.
• Unit: A unit is a subsystem, or a sub component or other entity within the system.
• Separator: Separator represents a boundary among sub systems, components or units.
• Group: Represents different header elements in the subsystem.