In the context of nutrition, which system is not directly related to waste secretion?

In the context of nutrition, the circulatory system is not directly related to waste secretion. Its primary role involves transporting nutrients, oxygen, and hormones throughout the body, as well as facilitating the removal of carbon dioxide and other metabolic wastes by delivering them to excretory systems. While it interacts with systems that handle waste, such as the urinary and digestive systems, its main function is not the direct secretion of waste.

The digestive system breaks down food and eliminates solid waste, while the urinary system is responsible for filtering blood and excreting liquid waste. The respiratory system helps remove carbon dioxide from the body through exhalation. Each of these systems has a more direct role in the process of waste management compared to the circulatory system, which serves as a transport network rather than a waste management system.