Final Answer:
A Organ System consists of a collection of organs and other body parts that work together to carry out the body's major functions. Thus the correct option is B. Organ System.
Step-by-step explanation:
An organ system is a collection of organs and other body parts that work in harmony to perform the fundamental functions required for the sustenance of an organism. In the human body, there are several organ systems, each specialized for specific tasks. These systems include the circulatory system, respiratory system, digestive system, and others, all collaborating seamlessly to maintain the body's overall health and functionality.
Firstly, an organism (option a) refers to an individual living being, encompassing all aspects of its existence, including its physical and physiological components. An organism can consist of various organ systems, which in turn are comprised of specific organs.
On the other hand, option c) Ecosystem pertains to a broader ecological concept involving interactions among living organisms and their environment, not specifically focusing on the internal workings of an individual organism.
Lastly, d) Tissue refers to a group of cells working together to perform a particular function. While tissues are essential building blocks, they are not comprehensive enough to encapsulate the intricate coordination found in an organ system.
In conclusion, the correct answer is b) Organ System, as it precisely captures the hierarchical arrangement of organs working collectively to ensure the proper functioning of the body's diverse and interconnected physiological processes.
Thus the correct option is B. Organ System.