What does the somatic nervous system primarily control?

The somatic nervous system is primarily responsible for the voluntary control of body movements. It consists of nerves that connect the central nervous system (CNS) to the muscles and skin, facilitating conscious movement and responses to the environment. When you decide to move your arm, walk, or perform any other physical activity, it is the somatic nervous system that enables these voluntary actions by transmitting the necessary signals from the brain to the appropriate muscles.

The other options refer to processes that are primarily controlled by other parts of the nervous system. For instance, involuntary body functions, such as heart rate and digestion, are regulated by the autonomic nervous system. Emotional responses can be influenced by various brain regions and systems that are not limited to the somatic nervous system. Additionally, digestive processes are also under the influence of the autonomic nervous system, which operates unconsciously. Thus, the role of the somatic nervous system in facilitating voluntary movement is distinct and essential, making it the correct answer.