Open circulatory system can contain_________?

Explanation

Open circulatory systems contain hemolymph, which may include circulating cells called hemocytes that perform functions comparable to white blood cells. Red blood cells and haemoglobin are characteristic of vertebrate blood and are generally absent from the hemolymph of animals with open circulation. Students may choose all of these because they are familiar components of vertebrate blood, but open systems do not generally contain red blood cells or haemoglobin.