Answer: Bar graphs show data involved in distinct categories that do not overlap; whereas, pie charts show data as parts out of a whole (such as out of 100%).
Explanation:
A bar graph, also called a bar chart, is used to present categorical variables, which involves rectangular bars with a correlation between a specific category and the frequency of them, this graphs can be also called histograms. It's used in statistics to describe a bunch a data, separating them in categories. This charts can be horizontal or vertical, and an important characteristics is that it's applied to represent discrete categories, that is, values expressed with whole numbers. (An example is attached).
On the other hand, pie charts, or circular charts, are used to indicate proportions from a whole part, like a pie or cake, you have a whole and 100% data and you divided into slices. For example, from the whole population in the U.S. we could divide it by ethnicity, parts from a whole, like show the image attached.
Therefore, based on each definition, the correct answer is:
Bar graphs show data involved in distinct categories that do not overlap; whereas, pie charts show data as parts out of a whole (such as out of 100%).