How does the circulatory system of an octopuses differ from a clams?

The circulatory system of octopuses is closed, meaning that blood is contained within vessels and circulated efficiently throughout the body, allowing for better oxygen delivery to their active tissues. In contrast, clams possess an open circulatory system, where blood flows freely through cavities and is not entirely contained within vessels, which can result in slower oxygen transport. Additionally, octopuses have a three-hearted system: two hearts pump blood to the gills for oxygenation, while the third pumps it to the rest of the body. Clams, on the other hand, rely on a simpler system that does not require multiple hearts for circulation.