Which type of chart can be used to represent trends over time?

A line chart is the most effective choice for representing trends over time because it displays data points connected by straight lines, which allows for easy visualization of changes and patterns over intervals. This type of chart is particularly useful when you want to illustrate how a particular value evolves, making it simple to discern trends, peaks, and valleys in the data over different periods.

For example, if you're tracking monthly sales data over a year, a line chart would clearly show fluctuations, allowing viewers to see increasing, decreasing, or stable trends at a glance. The ability to connect these points visually makes it easier for the audience to understand the temporal aspect of the data and to identify any significant shifts over time.

In contrast, a pie chart is designed to show proportions of a whole at a single point in time and would not effectively illustrate changes over periods. Bar charts and column charts can represent comparisons and trends to some extent but typically do not provide as clear a sense of progression over time as line charts do. They may group data into categories rather than showing a continuous flow, making it harder to track trends directly.