Final answer:
The largest group of organized living material forming organs is tissues. These collections of similar cells come together to carry out specific functions, further creating organs that partake in an organism's vital functions.
Step-by-step explanation:
The largest group of organized living material that makes up organs is tissues. Tissues are collections of similar cells that work together to perform a specific function within an organism.
In multicellular organisms, cells specialize and combine to form tissues, which then collaborate to create organs. Examples of tissues include muscle tissue, which allows for movement, and epithelial tissue, which forms the lining of internal and external surfaces. Organs are thus structured from these tissues to perform distinct functions necessary for the organism’s survival, such as the heart for pumping blood.
Furthermore, organs themselves work together to form organ systems such as the digestive or circulatory system. These systems are crucial for maintaining the various functions required for an organism's life processes. In summary, tissues are the critical building blocks that enable the formation of organs, which are then incorporated into organ systems.