Placenta functions as a carrier of nutrients from mother to baby. Thus all of amino acids, glucose, and oxygen will decrease in the concentration at 2 since all of them are transferred to the baby at 1 because it has a low concentration of all. However, due to metabolic processes and lack of excretory mechanism baby’s blood has a high concentration of carbon dioxide, which will be transferred to mother’s blood because her blood has low CO₂ concentration. Thus at 2 blood is coming at high CO₂ concentration.