What two structures compose the central nervous system?

The central nervous system (CNS) is composed of two primary structures: the brain and the spinal cord. The brain serves as the control center for processing information, coordinating movements, and regulating functions of the body, while the spinal cord acts as a communication highway that transmits signals between the brain and the rest of the body. This combination enables the CNS to effectively manage and integrate all neural activities.

Other options presented do not correctly identify the components of the CNS. The heart, while essential for circulation, is part of the cardiovascular system and not the nervous system. Similarly, while nerves and neurons play crucial roles in the peripheral nervous system, they aren't considered components of the CNS. Nerves are bundles of axons that transmit signals to and from the CNS, and neurons are the individual cells that process and transmit information. Thus, the correct answer highlights the specific structures that comprise the central nervous system itself.