In preparing a speech, a person outlines her main points as follows: $1)$ The information revolution is producing technologies that will alter our educational system. $2)$ The information revolution is rapidly changing the structure of the average person's workday. $3)$ The information revolution is on track to change even the way Americans spend their leisure time. In what way has the person arranged her main points? $1.$ Chronologically $2.$ Causally $3.$ Topically. $4.$ Spatially