Final answer:
Cells of a similar kind in living organisms are organized into tissues, which group together to form organs. These organs then work together as part of an organ system, exemplified by the circulatory system in mammals which includes the heart and blood vessels.
Step-by-step explanation:
In living organisms, cells of a similar kind are typically organized into what are known as tissues . These tissues are groups of similar cells that carry out similar or related functions. Going further up the hierarchy of biological organization, we find that organs are collections of tissues that work together to perform a common function. Moreover, multiple organs that are functionally related combine to form an organ system . This level of organization is critical in maintaining the complex functions necessary for life in larger multicellular organisms, such as mammals, which have diverse organ systems, including the circulatory system that involves the heart and blood vessels.
Overall, this hierarchy of structure proceeds as follows: atoms make up molecules, molecules make up cell components, cell components form cells, cells make up tissues, tissues combine to create organs, organs work together in organ systems, and organ systems support the entire organism, which is an individual living entity. Each level of organization is more complex than the one before, ensuring that life can be sustained and processes can be carried out efficiently.