Final answer:
Oxygen diffuses from the alveoli in the lungs to red blood cells and then from red blood cells to the mitochondria. Transport involves the binding of oxygen to hemoglobin within the red blood cells and the continuous exchange of gases facilitated by diffusion.
Step-by-step explanation:
Oxygen Transport to the Mitochondria
In the process of oxygen transport to the mitochondria, diffusion plays a crucial role. Oxygen enters the bloodstream from the lungs at the alveoli where it encounters pulmonary capillaries. Here it diffuses from an area of higher concentration in the alveoli to a lower concentration in the blood. The oxygen binds to hemoglobin in red blood cells (erythrocytes), forming oxyhemoglobin, which transports oxygen through the blood vessels to the body's tissues.
When red blood cells reach the tissues, oxygen is again released by diffusion from areas of higher concentration within the blood to the lower concentration in the cells, including the mitochondria, where it is utilized for cellular respiration. Carbon dioxide, a by-product, diffuses in the opposite direction from the cells to the blood. Thus, oxygen diffusion occurs in a continuous cycle from the lungs to the red blood cells and from red blood cells to the mitochondria.
So, the correct answer to the question is d. both the lungs to the red blood cells and the red blood cells to the mitochondria.
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