What type of graph is best to use to show changes over time?

Line graph

Bar graph display directly the varibales which are the rate and ratio of the numbers to visualize and display the results, these contrasting the different outcomes. On the contrary, histogram is used in grouped frequency parameters. Moreover, as little as the given five parameters or data set this will be ineffective and will result to a bar graph only and basically, the suited option is the aforementioned vertical graph to display the numbers. To expound on the definition of histogram it is used when the frequency is grouped. For example the data set of 1-5, 6-10, 11-15 and 16-20 this now can be used and applied to illustrate histogram because of the number and quantity of the given data. 

2xy/9 is the answer to this problem