Which of the following is NOT listed as an animal body system in the material?

• A. Musculo-skeletal system
• B. Digestive system
• C. Nervous system
• D. Skeletal system

Answer: (D)

The main idea is how body systems are grouped in the material. In many anatomy resources, the bones and muscles are combined into a single musculo-skeletal system because they work together to support the body, enable movement, and maintain posture. Since the skeletal components are already included within that combined system, the skeletal system is not listed as a separate, standalone system in that material.

So, the digestive system and the nervous system are treated as individual systems, and the musculo-skeletal system is the category that encompasses the bones plus the muscles. Because of that grouping, the skeletal system alone isn’t named separately.