Final answer:
During digestion, the Parasympathetic Nervous System is actively involved, as it controls the 'rest and digest' functions, which include stimulating digestive processes. In contrast, the Sympathetic Nervous System prepares the body for 'fight or flight' responses, and inhibits digestion.
Step-by-step explanation:
The nervous system regulates many functions in the human body, and when it comes to digestion, it is the Parasympathetic Nervous System that is primarily involved. The parasympathetic nervous system, often referred to with the epithet of 'rest and digest', is responsible for stimulating digestive activities, including the secretion of saliva and digestive enzymes, peristalsis (the movement of food through the digestive tract), and absorption of nutrients. In contrast, the Sympathetic Nervous System is associated with the fight-or-flight response, which includes accelerating heart rate and inhibiting digestion, to prepare the body for stress-related activities.
Therefore, in response to the question regarding which part of the nervous system is involved during digestion, the correct answer is B. Parasympathetic Nervous System.