Which structures are composed of gray matter?

The correct choice identifies the cerebral structures where gray matter is predominantly found. Gray matter consists primarily of neuronal cell bodies, dendrites, and synapses, and is crucial for processing information in the central nervous system.

The cerebellum, cerebrum, brain stem, and central spinal cord are all regions packed with gray matter, responsible for various functions such as motor control, sensory perception, and higher cognitive processes. In the cerebrum, for example, the gray matter forms the cortex, which is involved in processing sensory information and coordinating motor commands.

Other options describe structures or components that do not specifically consist of gray matter. Nerve fibers, which comprise white matter, connect different regions of the brain and spinal cord, primarily carrying signals rather than processing them. Neurons in synaptic connection could refer to both gray and white matter areas but does not specify the presence of gray matter structures, while all white matter structures consist of myelinated axons, which are distinctly different from gray matter.