Final answer:
The brain stem, part of the brain, controls many vital functions such as breathing and heart rate. It is the main link between the brain and spinal cord and manages most unconscious functions, including the regulation of the cardiovascular and respiratory systems.
Step-by-step explanation:
The brain, specifically the brain stem, is responsible for controlling many vital functions such as breathing (respiration) and heart rate. The brain stem is composed of three main parts: the midbrain, pons, and medulla. It is the main connection between the brain and the spinal cord, and command center for unconscious functions, controlling the head and neck region of the body through the cranial nerves. Additionally, there are control centers in the brain stem that regulate the cardiovascular and respiratory systems, making it the primary entity governing functions like heartbeat and breathing.
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