What do efferent nerves do in the somatic nervous system?

Efferent nerves in the somatic nervous system play a crucial role in transmitting signals from the brain to various parts of the body, particularly to skeletal muscles. This communication is essential for initiating voluntary movements—such as walking, picking up objects, or any physical activity that requires conscious control. When the brain generates a motor command, efferent nerves carry this signal through the spinal cord and out to the muscle tissues, resulting in muscle contraction and movement.

The other options address different aspects of the nervous system. For instance, relaying sensory information to the brain pertains to afferent nerves, which carry signals from sensory receptors to the central nervous system. Autonomic responses and involuntary bodily functions are typically managed by the autonomic nervous system, which handles processes like heart rate, digestion, and involuntary muscle contractions, rather than the voluntary control that efferent nerves execute in the somatic nervous system. Thus, the role of efferent nerves in facilitating voluntary muscle movement underscores why the chosen answer is accurate.