Which system is responsible for providing protection and immunity from harmful organisms?

The lymphatic system is crucial for providing protection and immunity against harmful organisms. It plays a vital role in the body’s defense mechanisms by filtering out pathogens and foreign substances. Lymph nodes, which are distributed throughout the body, help in trapping bacteria and viruses, while lymphocytes, a type of white blood cell produced in the lymphatic system, are essential for addressing infections and maintaining immune responses.

Additionally, the lymphatic system transports lymph, a fluid that contains infection-fighting white blood cells, thereby aiding in the overall immune response. It works closely with other components of the immune system, enhancing the body's ability to detect and respond to invaders effectively. This integration allows the lymphatic system to be considered a primary component of the immune defense network.

In contrast, while the cardiovascular system plays a role in circulating immune cells, it does not solely provide protection nor is it dedicated to immunity. The endocrine system regulates bodily functions through hormones but does not have a direct role in immune defense. The integumentary system, including the skin, acts as a physical barrier to some degree and contributes to immunity through various protective functions, yet it does not encompass the complex, adaptive immune responses that the lymphatic system manages.