Western Governors University (WGU) ICSC2100 C949 Data Structures and Algorithms I Practice Exam

Directed graphs are distinguished from undirected graphs primarily by the presence of direction in their edges. In a directed graph, each edge has a specific direction, which means it goes from one vertex to another in a particular orientation, often represented as an arrow. This indicates that there is a one-way relationship from the starting vertex (or "source") to the ending vertex (or "destination"). This characteristic is crucial in various applications, such as representing web pages with hyperlinks, where one page links to another without implying the reverse relationship.

In contrast, undirected graphs do not have directed edges; the connections between vertices are bidirectional. This means if there is an edge between two vertices, you can traverse it in either direction.

The other choices do not accurately reflect the fundamental distinction between these two types of graphs. Directed graphs do not inherently have more vertices than undirected graphs; both types can contain any number of vertices depending on how they are constructed. Additionally, while edges in undirected graphs can be weighted, this trait is not a defining aspect of undirected graphs and does not serve to differentiate them from directed graphs. Therefore, the defining characteristic of directed graphs having edges with direction is the key distinction.