Which statement correctly describes merging in Git?

Merging in Git is fundamentally about integrating changes from different branches to create a unified codebase. When you merge one branch into another, Git takes all the changes made in the source branch and applies them to the target branch, maintaining the history of all commits involved. This process ensures that a comprehensive view of the development work is preserved, allowing for collaboration among multiple contributors without losing their individual changes.

The nature of merging is collaborative and non-destructive, which means that it does not overwrite or discard previous work but rather brings it all together. This characteristic is essential for teams working on parallel features, as it allows them to combine their efforts seamlessly. By integrating changes, developers can ensure that new features and fixes are incorporated into the main codebase while preserving the integrity of the project's history.

The other options do not accurately describe the merging process in Git, as merging isn't inherently destructive, it does not alter existing commits, and it is applicable to both shared and non-shared branches, making option B a clear representation of merging's purpose within Git.