explain how carbon dioxide transport takes …

Exchange of gases takes place between the alveoli of lungs and the surrounding blood capillaries.  The two main gases exchanged are oxygen and carbon-dioxide. Oxygen is absorbed by the blood capillaries from the lungs alveoli by diffusion while carbon-dioxide is absorbed by the lungs alveoli from blood capillaries by diffusion.
Transport of oxygen and carbon-dioxide occurs with the help of respiratory pigment called hemoglobin.
Hemoglobin, the iron containing respiratory pigment is a red colored pigment of blood, which has a very high affinity for oxygen. Hemoglobin though is purple colored but oxy-hemoglobin is of bright red color. Oxygen is transported from lungs to the body cells in the form of oxy-hemoglobin.
Carbon-dioxide is transported from the body cell to the lungs in the forms of carboxy-hemoglobin, carbonic acid, bicarbonates of sodium and potassium.