Please help me 1. Trace the pathway of oxygen and CO2 in the blood through the respiratory system, circulatory system and the body. Include the words: right ventricle, left ventricle, right atrium, left atrium, trachea, lungs, pulmonary arteries, pulmonary veins, aorta, superior and inferior vena cava, arteries, veins, body cells, mouth/nose. 2. What is the importance of surface area to digestion? Describe the importance of surface area both for the food pieces and the digestive system itself.