What is the level of organization that groups together to become an organ system?

The level of organization that groups together to form an organ system is organs. Within the body, organs are structured groups of tissues that work together to perform specific functions. For example, the heart is an organ made up of muscle tissue, connective tissue, and other tissues that collectively work to pump blood through the body.

When multiple organs that perform related functions are grouped together, they create an organ system. For instance, the cardiovascular system consists of the heart and blood vessels, which collaborate to circulate blood. This hierarchical structure ensures that various functions within the body can be carried out efficiently.

In contrast, tissues are composed of similar cells working together to perform a function, while cells are the basic units of life. Atoms represent the smallest units of matter and form molecules, which are much simpler than the complex structures that comprise organs and organ systems. Therefore, understanding that organs represent the next level up from tissues, and are essential components that combine to make up organ systems, clarifies why this is the correct answer.