Scanning low allows you to locate obstacles [such as potholes] before you hit them. Scanning involves taking in the whole scene and happenings around your vehicle. This is done in order to perceive hazard early enough to take actions about it. Scanning low specifically involve looking down the road ahead of your vehicle in order to notice any hazard early and decide how to react to it.
Answer: C) only one main idea on each slide.
Eliza needs to be able to use her electronic slide presentation to convey what the purpose of the presentation is. By providing one main idea on each slide, this would show the audience of Eliza exactly what she wants to convey to them. This would also help her audience get on board of what the whole idea of the presentation is.