In Adobe Illustrator, what tool is used to create straight lines?

The Line Segment Tool is specifically designed for creating straight lines in Adobe Illustrator. When you select this tool, you can click and drag to draw a line from one point to another, defining its length and angle easily. This tool is straightforward and ideal for accurately creating lines without any curvature, making it perfect for geometric designs, diagrams, or any artwork requiring precise straight lines.

The Pencil Tool, while versatile, is primarily used for freehand drawing and allows for more fluid and organic line creation, which may result in curves rather than straight lines. The Brush Tool is similar in that it applies brush strokes to paths but is also oriented towards artistic and freeform line creation rather than straight lines. The Pen Tool, on the other hand, is excellent for creating paths that can include both straight lines and curves, but it requires a better understanding of anchor points and control handles, making it a more complex tool for the specific task of creating only straight lines. Thus, for simplicity and precision in straight line drawing, the Line Segment Tool is the most appropriate choice.