Final answer:
The cell is the lowest level of biological organization capable of performing all life functions. Cells form tissues, organs, and organ systems, culminating in an organism.
Step-by-step explanation:
The cells are the basic unit of life and are the smallest structures capable of maintaining life's functions, such as metabolism, growth, and reproduction.
In the biological hierarchy, cells assemble to form tissues, which then combine to form organs, which work together as organ systems. Ultimately, organ systems make up an entire organism, which is the highest level of biological organization.
For instance, in multicellular organisms like humans, various cells perform specific functions. These cells come together to form tissues like muscle or nervous tissues, which then help create organs such as the heart or the brain.
These organs work in a coordinated manner as part of organ systems, ensuring the organism can live and carry out various biological processes.