Which organ coordinates vital functions in the central nervous system of mammals?

The brain plays a crucial role in coordinating vital functions within the central nervous system of mammals. It integrates sensory information, controls motor functions, regulates bodily processes, and is responsible for higher cognitive functions such as reasoning, memory, and emotions. This central organ processes information from various parts of the body, allowing for coordinated responses to internal and external stimuli.

Although the brainstem is also involved in regulating basic life functions like breathing and heart rate, it is primarily a part of the brain and is not the entirety of the structure that coordinates all vital functions. The cerebellum primarily focuses on balance and coordination of voluntary movements, while the spinal cord serves as a conduit for signals between the brain and the rest of the body but does not coordinate functions independently. Thus, the brain, as the overarching coordinating organ, is indeed the correct choice.