Multicellularity is a research area in biology that focuses on the evolution and development of organisms made up of multiple cells working together. This phenomenon allows for increased complexity and specialization in organisms, as cells can differentiate and take on specific functions within the organism. Multicellularity has evolved independently in various lineages, providing insights into the genetic and molecular mechanisms that enable cells to cooperate and communicate in a coordinated manner. Researchers study multicellularity to understand how it evolved, its advantages and disadvantages, and how it contributes to the diversity of life on Earth.