Which systems are involved in digestive and metabolic functions?

The digestive and metabolic functions primarily involve the digestive and endocrine systems. The digestive system is responsible for breaking down food, absorbing nutrients, and eliminating waste, while the endocrine system plays a crucial role in regulating metabolism through the release of hormones, such as insulin and glucagon, which manage the body's energy use and storage. Both systems are essential for maintaining nutritional balance and overall health.

In contrast, the circulatory and respiratory systems, while vital for overall function, are not specifically involved in digestion and metabolism. The nervous and reproductive systems also do not directly contribute to these functions. Finally, the musculoskeletal and integumentary systems serve different purposes related to movement and protection but are not involved in digestion or metabolic processes. Therefore, the correct choice is the digestive and endocrine systems, as they directly facilitate the processing and utilization of nutrients in the body.