The interaction of which two systems provides the molecules needed for the metabolic activity that takes place at ribosomes?

The interaction of the endocrine system and the circulatory system provides the molecules needed for the metabolic activity that takes place at ribosomes. The endocrine system regulates the release of hormones that signal cells to produce specific molecules, and the circulatory system transports these molecules to the cells, including ribosomes, where they are used for metabolic processes.