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

A stack data structure is characterized by its Last In First Out (LIFO) principle. This means that the last element added to the stack is the first one to be removed. Think of it like a stack of plates; you always add to the top and remove from the top. This behavior is essential in various applications like function call management in programming languages, where the most recently called function needs to be resolved first.

In contrast, options that mention First In First Out (FIFO) principles describe a queue structure, where the first element added is the first one to be removed. Sorting does not specifically define a stack or its behavior; while elements can be sorted after they are stored, it does not capture the essence of how a stack operates. Lastly, the notion of holding unordered values does not align with the specific, structured way that stacks function, where elements are added and removed in a well-defined manner according to LIFO.