To animate a line graph in PowerPoint, you need to open the slide, draw the Graph add the labels and then animate the graph as explained here.

We show you how to create a Histogram chart in Microsoft PowerPoint. A Histogram is a graphical representation that shows frequency data.

Start the PowerPoint application and use the "File" menu to open the presentation containing the graph to which you wish to add the callout.

Removing data from a chart in PowerPoint 2010 is similar to creating one. You choose to edit the chart and the familiar Microsoft Excel window pops up, enabling you to remove columns, rows and cells.