Which system includes lymph, lymph nodes, and lymph vessels?

The lymphatic system is fundamentally responsible for transporting lymph, a fluid that contains infection-fighting white blood cells, throughout the body. It includes lymph, which is the fluid itself; lymph nodes, which are small structures that filter lymph and help in the immune response; and lymph vessels, which are conduits that transport lymph from tissues to the bloodstream.

The lymphatic system plays a crucial role in maintaining fluid balance in the body, absorbing fats from the digestive system, and providing a pathway for the immune responses to occur. By filtering and monitoring lymph, lymph nodes can detect and respond to pathogens, which is essential for immune defense.

In contrast, the endocrine system regulates body functions through hormones, the respiratory system is involved in gas exchange, and the digestive system processes food and absorbs nutrients. None of these systems are directly concerned with the transport and filtration of lymph. Therefore, the identification of the lymphatic system as the correct answer highlights its unique and critical contributions to bodily health and immunity.