The correct answer is an organ. Organs are structures made up of two or more types of tissues that work together to perform specific functions within the body. For instance, the heart comprises muscle tissue, connective tissue, and nerve tissue, all of which collaborate to facilitate blood circulation.
In contrast, a system refers to a group of organs that work together to carry out a particular task, such as the circulatory system. A cell is the basic unit of life, consisting of various organelles and structures, but it is not made up of tissues. A tissue, on the other hand, is a group of similar cells that perform a specific function, but it does not consist of multiple types of tissues as organs do. Thus, the definition of an organ as a collection of similar tissues performing a common function emphasizes its distinct role in bodily organization and function.