The Correct answer is Only four. Explanation & Key Takeaways: • The human heart has four chambers which include the right atrium, right ventricle, left atrium, and left ventricle. Hence option 1 is Correct. • The heart is a muscular organ that pumps blood through the blood vessels of the circulatory system. In humans, heart is located between the lungs in the middle compartment of the chest and its size is approximately the size of a closed fist. • Atrioventricular valves are the valves between the atria and ventricles of the heart. • Nowadays, the most common cause of death is Cardio vascular diseases which is caused by the following factors being overweight, smoking, high blood pressure, high cholesterol, etc. • The human circulatory system consists of a network of arteries, veins, and capillaries, with the heart pumping blood through it. • Its primary role is to provide essential nutrients, minerals, and hormones to various parts of the body. • Alternatively, the circulatory system is also responsible for collecting metabolic waste and toxins from the cells and tissues to be purified or expelled from the body. +------------------------+-----------------------------------------------------------------------------------+ | Parts | Function | +------------------------+-----------------------------------------------------------------------------------+ | Superior vena cava | carries blood from the head, neck, arms, and chest | | Inferior vena cava | carries oxygen-depleted blood back to your heart from the lower part of your body | | Left pulmonary artery | Supplies blood to the left lung | | Right pulmonary artery | Supplies Blood to the right lung | | Left pulmonary vein | transfer oxygenated blood from the lungs to the heart. | | Right pulmonary vein | transfer oxygenated blood from the lungs to the heart. | +------------------------+-----------------------------------------------------------------------------------+