Final answer:
The organism level includes all other levels of organization.
Step-by-step explanation:
The organism level includes all of the other levels of organization mentioned in the list, which are cell, tissue, organ, and population. An organism is a living being that can independently perform all physiologic functions necessary for life. In multicellular organisms, cells combine to form tissues, which further combine to form organs, organ systems, and ultimately, the complete organism. For example, in a human body, cells combine to form tissues such as muscle tissue, which further combine to form organs like the heart, and all the organs collaborate to form the human organism.