In Microsoft Excel, to draw attention to a specific marker in a line chart, drop in a thin line, think of it as a marker.

How to Change Grid Line Colors on a Chart With Microsoft Excel. Grid lines add horizontal and/or vertical lines to your graph that aid in measuring graph values. By default, these grid lines use ...

Learn how to draw and understand information presented by a line graph with this interactive guide by BBC Bitesize for KS2 pupils.