Answer:
D. the high partial pressure of oxygen in the lungs
Step-by-step explanation:
- As the cells of the human body are made of the Hemoglobin molecules that transport this red blood to the bloodstreams.
- Due to the presence of the dissolved oxygen concentration in the body that these molecules in the lungs are unloaded and then merges with the tissues.
- The higher pressure is responsible for the flow of the oxygen in the lungs and the thus formation of the RBC in hemoglobin.