What is the main role of the spleen?

The main role of the spleen is to filter blood and recycle iron, which makes this choice accurate. The spleen is an essential component of the lymphatic system and plays a critical role in the immune response. It acts as a blood filter, removing old or damaged red blood cells from circulation. During this process, the spleen breaks down hemoglobin from these cells, allowing for the recycling of its components, including iron. This recycled iron can then be used in the synthesis of new hemoglobin for healthy red blood cells.

The spleen also helps in the storage of white blood cells and blood itself, contributing to the body's defense mechanisms against infections. It serves as a site for the proliferation of lymphocytes, which are crucial in responding to pathogens in the blood.

In contrast, the other functions listed in the other choices do not pertain to the spleen. Producing insulin is a role fulfilled by the pancreas; regulating body temperature is primarily managed by the hypothalamus; and storing bile is a function of the gallbladder.