Answer:
An organism would need a 4 chambered heart.
Explanation:
The heart consists of 4 chambers in which blood flows freely. Right atrium, left atrium, left ventricle and right ventricle.
The pulmonary arteries carry de-oxygenated blood to the lungs from where CO2 is released and O2 is picked up during the process of respiration. The pulmonary vein then takes the oxygenated blood to the left atrium of the heart and then to the left ventricle of the heart.
