Which system helps maintain fluid balance and immune functions in the body?

The lymphatic system plays a crucial role in maintaining fluid balance and supporting immune functions in the body. This system is responsible for collecting excess fluid, known as lymph, from tissues and returning it to the bloodstream, which prevents swelling and helps manage fluid levels in the body. Additionally, the lymphatic system is integral to the immune response; it transports lymphocytes, which are white blood cells essential for fighting infections. The lymph nodes, part of this system, filter lymph and trap pathogens, enabling the body to mount an immune response when necessary.

In contrast, the respiratory system primarily focuses on gas exchange, bringing oxygen into the body and expelling carbon dioxide. The nervous system coordinates bodily functions and responses to stimuli but does not directly manage fluid balance or immune responses. The skeletal system provides structure and support to the body and plays a role in the production of certain blood cells but is not involved in fluid regulation or immune functions. This distinction highlights why the lymphatic system is the correct choice for maintaining fluid balance and supporting immune functions.