<u>It would be difficult to plot a line of best fit on the scattered graph of the activities of metal blocks as the activities would almost be the same horizontally on the graph</u> and an attempt to draw/determine an intercept will be almost impossible. The line of best fit is usually drawn to determine the relatedness/correlation of the variables.
Drawing intercept for the activities of the liquid is easier because a line of best fit can be easily placed between the clustered liquid activities on the scattered plot.