Answer:
Blood vessels (Veins)
Explanation:
Blood vessels are vessels in the human body that helps in the circulation of blood being pumped from the heart.
There are five types of blood vessels namely:
Arteries: helps in carrying oxygenated blood away from the heart to other parts of the body.
Veins: helps in carrying deoxygenated blood back to the heart.
Capillaries: are tiny vessels that connect the venules to arterioles, they allow nutrients from the blood to pass into the body tissues and also waste products from body tissues pass into the capillaries.
Venules: collects blood from the capillaries and sends it to the veins.
What would happen if M RNA were radio actively labeled instead of polypeptides is that instead of one seeing the DNA passing through all the molecular factories you will instead see just messenger RNA taking code and delivering it to Ribosome. This is mainly found in cytoplasm and Endoplasmic recticulums.
Heterogeneous, because you can take out or sort the ingredients in all three into separate parts