The primary tool used for version control in software development is Git. Git is a distributed version control system that allows multiple developers to collaborate on a project while maintaining a comprehensive history of changes. It facilitates branching and merging, enabling teams to work on new features or fixes independently before integrating them back into the main codebase. By tracking changes over time, Git helps prevent conflicts and ensures that all contributions are documented. Popular platforms like GitHub and GitLab further enhance collaboration and project management within development teams.