World of Biology on Instagram: "Blood circulation is the continuous flow of blood throughout the heart and blood vessels. It delivers oxygen and essential nutrients to every cell while removing carbon dioxide and other waste products. Driven by the heart’s pumping action, arteries transport oxygen-rich blood from the heart, while veins carry oxygen-poor blood back for reoxygenation. This vital system keeps your organs functioning, your brain alert, and your body energized around the clock. #biol