Final answer:
Tissues made up of cells come together to form organs, which in turn work together as part of an organ system, and when various organ systems function in unison, they make up an organism.
Step-by-step explanation:
Tissues are composed of cells, and tissues functioning together make up organs. In the human body, similar cells form tissues, and these tissues come together to perform specific functions, forming an organ. Examples of organs include the heart, brain, and stomach. When various organs work in coordination, they form organ systems, such as the circulatory system and the digestive system. A complete living entity, like a human or a tree, is known as an organism.
Cells are considered the basic unit of life in all living things. Each cell contains organelles that carry out vital functions within the cell. When several cells of one kind interconnect and perform a shared function, they form a tissue. Moving up the complexity scale, several tissues combine to create an organ, and multiple organs make up an organ system. Finally, several organ systems functioning together lead to the formation of an organism.