How do activities with prerequisites begin in a directed network?

In a directed network, activities with prerequisites begin at the same predecessor at the same vertex because they rely on the completion of a previous task before they can commence. This means that these activities are dependent on the same initial event or task, represented as a common vertex in the network.

When multiple activities share prerequisites, they can all start simultaneously after the prerequisite activity has been completed. Each of these activities can be represented as an outgoing edge from the shared starting vertex to their own respective ending vertices. This coordinated start ensures that all necessary prerequisite conditions are fulfilled before moving forward.

The reasoning behind the choice centers around the structural properties of directed networks, emphasizing how dependencies are represented and managed through vertices and edges. Other choices do not accurately reflect this structural arrangement, as they suggest individual or separate beginnings that do not capture the essence of prerequisite relationships.