<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.
The majority of the mass of the atom is located in the nucleus. Remember that the nucleus contains both protons and neutrons and therefore, most of the mass of the atom.