Step 1: Understand that DFS stands for Depth-First Search, which is a way to explore or traverse a graph or tree.
Step 2: Know that in DFS, we need to keep track of which vertices (or nodes) we have visited.
Step 3: Learn that a stack is a data structure that works on a Last In, First Out (LIFO) principle, meaning the last item added is the first one to be removed.
Step 4: Realize that DFS uses a stack to remember the vertices we need to visit next.
Step 5: Understand that we can use a stack explicitly (by creating one) or implicitly (by using the call stack through recursion).
Step 6: Conclude that the primary data structure for DFS is a stack.
