What does a Git merge accomplish?

A Git merge integrates changes from one branch into another, effectively combining the histories of both branches. When you merge, Git takes the changes made in a specific branch and applies them to the branch you are currently working on, leading to a unified version of the project that includes all contributions from both branches. This is a fundamental aspect of version control as it allows teams to work on different features or fixes in isolated branches and then seamlessly bring those developments together into the main codebase.

The other options do not accurately depict the function of a Git merge. Deleting the older branch would not occur automatically with a merge; branches can be retained for further work and reference after they have been merged. Creating a backup of the current branch is not a purpose of merging—while you might consider making a backup before merging, the merge itself does not serve this purpose. Lastly, preventing changes in the current branch is contrary to the very nature of merging; a merge is intended to introduce changes rather than inhibit them.