Galaxy populations refer to the distribution of different types of galaxies across the universe. This research area involves studying the properties, characteristics, and behavior of galaxies in order to understand their formation, evolution, and interactions with other galaxies. Scientists classify galaxies into different populations based on their size, shape, color, and other features, and study how these populations change over time and in different environments. By studying galaxy populations, researchers can gain insights into the processes that shape the structures of the universe and the origins of galaxies.