Which graph would best represent the change in European population over time?

A line graph is the most effective choice for representing changes in population over time due to its ability to illustrate trends and developments across a continuous timeline. By connecting individual data points with lines, it allows the viewer to easily visualize how the European population has increased or decreased over specific intervals.

In the context of historical data, fluctuations in population can reflect various factors such as migration patterns, economic conditions, and significant events like wars or epidemics. The line graph effectively captures these trends, making it straightforward to interpret periods of rapid growth or decline.

Bar graphs, while useful for comparing quantities at a specific point in time, do not effectively show changes over intervals. Pie graphs are better suited for illustrating proportions at a single moment rather than changes over time. Scatter plots can show relationships between two variables but are not ideal for depicting a single variable's progression, such as population over time. Thus, the line graph stands out as the most appropriate choice for conveying this type of information.