While prewriting a paper about the two sides during the Civil War, Phillip used a t-chart to organize his thoughts. On one side of the chart he wrote the title "Confederate Army,” and on the other side he wrote "Union Army.”

What should be placed on either side of the vertical line?

only battles between the Confederate Army and the Union Army
minor points about the Confederate Army and Union Army
only opinions about the Confederate Army and Union Army
key points about the Confederate Army and Union Army