Answer:
1. The girl
2. To add depth, so people are drawn to the image.
3. The diagonal lines, because the help create a sense of movement and change.
Explanation:
1. It's a very simple concept that consists of placing your main subject somewhere near the lower, upper, left or right third of your photo scene. As you do this, your subject will become the focal point.
2. Background lines can also be used to create a sense of movement in your images, or to convey a sense of distance or depth. Converging lines that disappear into the distance are a great example of lines that help to draw the viewer into the image, while adding a sense of depth.
3. Good photographers are capable of creating images that naturally draw your eye along subtle, organic lines to a specific focal point. In order to achieve this effect, many skilled photographers use a compositional tool known as leading lines. Leading lines are incredibly effective at directing a viewer’s attention, and learning how to use them will greatly improve your photography composition.