Cell types refer to the distinct categories or classifications of cells that make up the different tissues and organs in the human body. Each cell type has specific functions and characteristics that help to maintain the overall health and function of the body. Research in this area focuses on identifying and characterizing the various cell types, understanding their roles in different physiological processes, and exploring how changes in cell types can contribute to the development of diseases. This field of study is essential for advancing our understanding of human biology and could lead to the development of new therapies and treatments for various health conditions.