After the Olympic flame ascended Mount Everest, more and more mainland tourists visited Tibet. The curve in the picture can accurately represent the red blood cells of Teacher Zhao from Beijing to Tib

After the Olympic flame ascended Mount Everest, more and more mainland tourists visited Tibet. The curve in the picture can accurately represent the red blood cells of Teacher Zhao from Beijing to Tibet.

There is a red iron-containing protein called hemoglobin in red blood cells. The reason why red blood cells are red is because they contain hemoglobin. Characteristics of hemoglobin: In places with high oxygen content, it is easy to combine with oxygen; in places with low oxygen content, it is easy to separate from oxygen. This characteristic of hemoglobin enables red blood cells to transport oxygen. Compared with plain areas, plateau areas have less oxygen in the air. In this environment, in order to adapt to the hypoxic environment, the human body will slowly increase the number of red blood cells and hemoglobin content in the blood, thereby enhancing the oxygen supply capacity of the blood. After increasing to the required amount, it will tend to To be stable. This is an adaptive change of the human body to the environment. It can be seen that C is consistent with the meaning of the question.

So choose: C