4. The writer application opens a blank document, it displays a vertical blinking line called ___

The vertical blinking line that appears in a blank document when you open a writer application is called the "insertion point" or "cursor." It indicates the location where text will be inserted when you start typing. The insertion point moves as you type, allowing you to see where each new character will appear in the document. This feature is crucial for text editing and formatting, as it provides a visual cue for users to keep track of their position in the document. The insertion point can also be moved using the arrow keys or mouse, enabling users to edit existing text or insert new content at any location within the document.