Which of the following is NOT one of the 11 body systems?

The question asks for a system that is not one of the 11 recognized body systems. The correct answer is the cardiovascular system, commonly associated with circulation and blood flow, which is indeed one of the main body systems.

To understand this further, the human body is commonly divided into 11 body systems, which include the integumentary, skeletal, muscular, nervous, endocrine, circulatory (or cardiovascular), lymphatic, respiratory, digestive, urinary, and reproductive systems. Each of these systems plays a vital role in maintaining homeostasis and overall bodily function.

In this context, both the endocrine and lymphatic systems are recognized as essential components of the body's organization. The digestive system is also crucial as it processes food and absorbs nutrients. Therefore, the cardiovascular system is definitely included among the standard classifications of body systems, making the provided answer inaccurate as it mistakenly identifies a recognized system as not part of the list.