____ are represented in the Timeline with a solid circle inside gray shading.

A(n) ________ has an extra layer of special ink in which tiny, precise patches are burned causing them to block light

Fill in the blank(s) with correct word

?In a use case, the _____ is shown as a stick figurewith a label that identifies its role.

A. ?actor B. ?association C. ?linkage D. ?service request