高空抛物现象被称为“悬在城市上空的痛”．据报道：一个30g的鸡蛋从25楼抛下可使人当场死亡．是因为：鸡蛋的　____ 　，重力势能与高度有关，下落过程　____ 　，动能大，所以危险性大．

根据短文理解, 从A、B、C三个选项中选择最佳答案填空。

    Miss Richards was a teacher at a school for boys and girls. She 1 chemistry and physics from the lowest to the highest classes in the 2. Sometimes the new classes 3 rapidly, but sometimes they were very 4, and then Miss Richards had to 5things many times.

    One year, the first class had been studying chemistry for several 6 when Miss Richards suddenly asked, "What is water? Who knows? 7 up!"

    There was silence for a few seconds, and Miss Richards felt sad, but then one boy 8 his hand.

    "Yes, Dick?" said Miss Richards encouragingly. He was not one of the brightest children in the class, so she was 9 that he could answer.

  "Water is a liquid which has no 10 until you wash your hands in it, Miss. Then it turns black, "the boy replied with great confidence.

材料一：外争主权，内除国贼，反对在对德“和约”上签字，惩办国贼曹汝霖等人。
——“五四”口号
材料二：“在‘五四’运动……之际，我们回顾历史，缅怀先烈，进一步弘扬伟大的‘五四’精神，这对于激励广大青年同全国各族人民一道实现中华民族伟大复兴而不懈奋斗，具有十分重要的意义。”
——李长春讲话

下列关于人体内环境稳态与调节的叙述，错误的是（　　）