In the human body, is every organ a part of only one organ system? Or are some organs a part of two or more organ systems? A. Every organ is a part of only one organ system, which is necessary because organ systems work independently of one another. B. Every organ is a part of only one organ system, although organ systems often interact with one another. C. Some organs are a part of two or more organ systems. For example, the heart is a part of the circulatory and digestive systems. D.