Final answer:
Traversing a tree is the correct term for visiting each element in a tree data structure. Traversal methods include in-order, pre-order, post-order, and level-order. Other options such as inserting, merging, and sorting are different operations not specifically associated with tree traversal.
Step-by-step explanation:
Visiting each element in a tree data structure is known as traversing. To traverse a tree means to go through all the nodes and process them accordingly. There are several common methods of tree traversal, which include in-order, pre-order, post-order, and level-order traversals. Each of these methods serves different purposes and is used depending on what needs to be achieved. In-order traversal is often used for binary search trees as it retrieves data in sorted order, pre-order traversal is used to create a copy of the tree, post-order traversal is useful for deleting the tree, and level-order traversal is used to visit nodes level by level.
Options a, 'Inserting,' and e, 'Sorting,' refer to different operations on a tree. 'Inserting' is the process of adding a new node to the tree, while 'Sorting' is an operation typically associated with organizing data in a specific order, though not a traversal method itself. 'Merging' is not a term specifically associated with a single tree traversal operation, although it could be involved in some algorithms that manipulate multiple trees.