What is the main role of the lymphatic system in the body?

The main role of the lymphatic system in the body is to protect against infection. This system is a crucial component of the immune system, as it is responsible for the production and transport of lymph, which contains infection-fighting white blood cells. The lymphatic vessels circulate lymph throughout the body, collecting and filtering out pathogens, cellular waste, and excess fluids from tissues. This process not only helps prevent infections but also supports overall immune function by facilitating the movement of immune cells to areas where they are needed to combat pathogens.

The other options do not accurately reflect the primary function of the lymphatic system. While metabolism is regulated by other systems in the body, oxygen transportation is primarily carried out by the circulatory system through red blood cells, and digestion is handled by the digestive system. Thus, the lymphatic system's unique role in immune defense distinguishes it from these other bodily functions.