What system consists of organs, tissues, and vessels that maintain the fluid balance of the body and contribute to immune function?

The lymphatic system is responsible for maintaining fluid balance in the body and plays a crucial role in immune function. It consists of a network of lymphatic vessels, organs like the spleen and thymus, and lymph nodes that facilitate the transport of lymph—a fluid that contains infection-fighting white blood cells. When tissue fluid accumulates due to factors such as infections or inflammation, the lymphatic system helps to drain excess fluid and return it to the bloodstream, thus preventing edema and maintaining homeostasis.

Additionally, the lymphatic system is instrumental in the immune response, as it helps in the production and transportation of lymphocytes (a type of white blood cell) and filtering out pathogens through lymph nodes.

In contrast, other systems mentioned in the options serve different primary functions. The respiratory system is essential for gas exchange, the circulatory system is mainly involved in transporting blood, nutrients, and gases, and the nervous system is responsible for coordinating bodily functions and responses. Each of these systems plays vital roles, but none of them specifically focus on fluid balance and immune function in the way the lymphatic system does.