Final answer:
In all animals except sponges, cells differentiate into specialized tissues, which include nervous, muscle, connective, and epithelial tissues, to perform distinct functions within the body. This differentiation is essential for developing the complex structure of organs and organ systems in multicellular organisms.
Step-by-step explanation:
In all animals except sponges, cells differentiate into specialized tissues which are groups of cells that take on particular functions in the animal's body. These specialized cells are a fundamental characteristic of multicellular organisms. Different types of cells such as nerve cells, muscle cells, and epidermal cells are examples of how cells are specialized to perform specific functions within the body.
During the development of an organism, cellular differentiation is the crucial process whereby stem cells become specialized. This leads to the formation of tissues that are collections of similar cells with a common embryonic origin. The main tissue types in animals are nervous, muscle, connective, and epithelial, each having different roles. For instance, nervous tissues contain neurons that transmit nerve impulses, while muscle tissues are involved in body movement.
Specialized cells can be organized into tissues, which further combine to form organs and subsequently organ systems, creating a complex, functioning organism. This organized structure allows for effective performance and maintenance of the body's functions, ultimately contributing to the survival and reproduction of the organism.