Breathing, heart rate, and blood pressure are controlled by which nervous system?

The correct answer is the autonomic nervous system. This system is responsible for regulating involuntary bodily functions, which include breathing, heart rate, and blood pressure. The autonomic nervous system operates without conscious control and plays a vital role in maintaining homeostasis in the body. It is divided into two main branches: the sympathetic nervous system, which prepares the body for 'fight or flight' responses, and the parasympathetic nervous system, which promotes 'rest and digest' activities.

The somatic nervous system, in contrast, controls voluntary movements and is responsible for the conscious control of skeletal muscles. It does not regulate involuntary processes like heart rate or blood pressure.

The term 'automatic' could be misleading in this context, as it is not a recognized category in the study of the nervous system.

The peripheral nervous system encompasses all nerves outside of the brain and spinal cord, including both the somatic and autonomic nervous systems, but it does not specifically control the functions mentioned in the question.

Thus, the autonomic nervous system is the most accurate answer as it directly correlates with the regulation of involuntary physiological processes such as breathing, heart rate, and blood pressure.