人有许多血型系统，如ABO血型、MN血型等．研究表明，人的ABO血型不仅由位于9号染色体上的I^A、I^B、i基因决定，还与位于第19号染色体上的H、h基因有关．在人体内，H物质在I^A基因的作用下，形成凝集原A；H物质在I^B基因的作用下形成凝集原B；而ii的人不能转变H物质．其原理如图所示：

请根据上述信息回答下列问题：

根据短文理解，从A、B、C、D四个选项中选择最佳答案填空。

    Check out any woman's wardrobe and you will be sure to find at least one pair of high heel shoes there. After all, which woman can     1 wearing something that makes her look taller and her legs 2 longer? Unfortunately, those high heel shoes women love so much 3 their name, and can end up doing more damage than you can imagine 4 the spine(脊柱) and lower back—if care is not taken.

    Murlowska, a therapist(治疗师 ), is 5 with the consequences of wearing high heels. A majority of 6 who arrive at Murlowska's office come to her with back and lower back problems. Very often the 7 are the result of not walking properly in high heels or choosing the 8 kind of footwear.

    "I know women love wearing high heels but they can 9 extreme damage to the body," Murlowska says, "I recently had a patient who had a terrible fall while walking in high heels and twisted her  10. She did not think much of it at the time, but the next morning she 11 up to find her knee swollen and painful."

    If a woman walks in heels 12 than five centimeters, several pressure points develop in various parts of the body which experience 13. Essentially, a woman wearing high heels is attempting to  14 her entire body on a very small area. This causes extreme stress on the muscles of the legs 15 increasing the chances of the ankle getting twisted. This can 16 damage to the knee ligaments(韧带) and tendons(腱). High heels force the 17 into an unnatural down-turned position. Consequently, the rest of the body has to 18 itself in order to stay balanced. The lower part of the spine as well as the hip bone tilts(倾斜) forward while the 19spine and the neck tilts back in order to maintain balance."

    Over a period of time, the hip bone also gets 20 because of the change in the center of gravity as a result of wearing high heels.