Which of the following organs is part of the musculoskeletal system?

The correct answer is the joints, as they are integral components of the musculoskeletal system. The musculoskeletal system is responsible for providing bodily support, enabling movement, and protecting vital organs. It consists of bones, muscles, tendons, ligaments, and joints. Joints specifically are where two or more bones meet, allowing for flexibility and movement, which demonstrates their essential role in the overall functioning of the musculoskeletal system.

In contrast, the heart and liver are part of the cardiovascular and digestive systems respectively, while the kidneys are part of the urinary system. Each of these organs has distinct functions that do not relate to the support and movement characteristics that define the musculoskeletal system.