What type of visualization is best suited for showing changes in a single variable over time?

A line graph is particularly effective for depicting changes in a single variable over time because it connects individual data points with a continuous line, allowing for a clear representation of trends, fluctuations, and patterns. The X-axis typically represents time, while the Y-axis shows the value of the variable being measured. This format enables viewers to easily track the progress and make comparisons at different points in that time series, making it a powerful tool for time-based analysis.

Other visualization types, while useful in different contexts, do not convey the same depth of temporal change. For instance, a bar chart can effectively show individual values at specific time intervals but may not clearly illustrate trends over time as line graphs do. A pie chart is useful for displaying proportions at a single point in time but does not depict changes or trends over time. A bubble chart, while visually appealing and capable of showing relationships between multiple variables, may complicate the representation of a single-variable trend, making it less suited for clear temporal analysis. Thus, the line graph stands out as the most appropriate choice for visualizing changes in a single variable over time.