What is the function of the lymphatic system?

The lymphatic system plays a crucial role in maintaining fluid balance in the body and protecting against infections. It helps to transport excess interstitial fluid, also known as lymph, back to the bloodstream, preventing conditions such as edema, which occurs when fluid accumulates in tissues. Additionally, the lymphatic system is vital for immune function. It contains lymph nodes and lymphocytes (a type of white blood cell) that help to identify and eliminate pathogens and foreign materials, thereby protecting the body from infections and diseases.

While other systems mentioned in the options have specific functions—such as the circulatory system managing blood flow, the endocrine system regulating hormones, and the musculature controlling movement—none of these encompass the dual roles of maintaining fluid equilibrium and providing immune response that are central to the lymphatic system's purpose. This highlights why the answer focusing on fluid balance and protection against infections is the most accurate representation of the lymphatic system's function.