Answer:
Scroll Bar
Explanation:
Mouse Scroll Bar is used for moving horizontally and vertically through a presentation slide with a pointer.
When your slide is large and not fit in specific view mode, you can use mouse scroll bar to move the slide horizontally or vertically to see the slide contents.
for example, if you zoom in more than 100% then the contents of slide become obsolete for viewing. To view the contents, you can use this graphical device to see the contents of slide while moving horizontally or vertically.