Question

2. When humans exhale, carbon dioxide leaves the body. Describe where carbon dioxide comes from and how the human body expels it?

Answer 1

carbon di oxide comes from blood.... it expels through respiratory organ which are lungs... :)

Answer 2

The respiratory system consists of inhalation of oxygen inside the body and exhalation of carbon dioxide out of the body. The oxygen comes from the outer environment and enters into the human body.

It reaches the lungs and gets mixed into the blood and then it travels to the various organs of the body. The organs diffuse the carbon dioxide into the blood reaching the organs.

Then this blood is again returns to the lungs for exchange of gases.