4
JavaScript is a programming language.
When people want to show off code to each other they can put it on GitHub. When people want to work togheter on a project they can each work on their local computer and push the changes on Github. When people want to work on a project and register the changes they made tey can do so by creating branches and commiting the changes on Github.
You copy it to your Github account.
It send it to your local computer.
Pull Request is a request to merge changes from one branch into another in a GitHub repository.