A. ggplot2 is a popular data visualization package in R that allows users to create sophisticated and customizable graphics with ease. It is based on the concept of a "grammar of graphics," which means that it provides a flexible and consistent framework for creating a wide range of visualizations, including scatterplots, line graphs, bar charts, histograms, and more. ggplot2 offers many features for customizing the appearance of visualizations, including color, font, size, labels, and annotations.