Prompt: In the blood vessels, ribosomes are not directly present or actively functioning. Ribosomes are organelles that function within the cytoplasm of cells, whereas blood vessels are mainly part of the circulatory system, delivering oxygen, nutrients, and other substances to various cells through the bloodstream. Ribosomes inside the cells play a role in protein synthesis, converting amino acids obtained from the bloodstream into proteins to maintain normal cell functions. Therefore, although ribosomes play a crucial role within cells, they are not actively part of the blood vessels themselves.