🩸🟥vs💧🟦

#blue blood #red blood comparison #hemoglobin contrast #respiratory pigment color #copper vs iron #invertebrate blood

🐙💙

#invertebrate blood #mollusk blood #cephalopod blood #blue blood #oxygen transport protein #copper protein

🐙🩸🔵

#octopus blood #squid blood #hemocyanin #invertebrate blood #cephalopod physiology #copper-based blood