For points

after a chart has been inserted and formatted, is it possible to change the data range it refers to or to add new rows of data?

a: no, additional data cannot be included in a chart once it has been created; the user should delete the chart and create a new chart.
b: yes, click the select data button in the data group under the design tab to extend or reduce the data range.
c: yes, click the chart, select the additional rows or columns of data to add, and press enter on the keyboard.
d ; yes, double-click the chart and select properties from the list; in the properties box, insert the new data range to include in the chart.