2017届高考英语二轮专题复习精品之A breathtaking trick potentially left over from our ancestors might be found in us — the ability to sense oxygen through our skin.

　　Amphibians(两栖动物), animals such as frogs that can live both on land and in water, have long been known to be capable of breathing through their skin. In fact, the first known lungless frog that breathes only through its skin was discovered recently in the rivers of Borneo.

　　Now the same oxygen sensors found in frog skins and in the lungs of mammals have unexpectedly been discovered in the skin of mice.

　　“No one had ever looked,” explained Randall Johnson, a biologist researcher.

　　Mice and frogs are quite distant relatives, so the fact they have these molecules (分子) in common in their skin suggests they might well be found in the skin of other mammals, such as humans.

　　“We have no reason to think that they are not in the skin of people too,” Johnson said.

　　These molecules not only detect oxygen, but help increase levels of vital red blood cells, which carry oxygen around the body. Normal mice breathing in air that is 10 percent oxygen—a dangerously low level similar to conditions at the top of Mount Everest, and about half that of air at sea level. However, mice that had the oxygen sensor HIF-1 a genetically removed from their skin failed to produce this hormone (荷尔蒙) even after hours of such low oxygen.

【2017届高考英语二轮专题复习 阅读理解部分之限时训练（四）】相关文章：

★ 2017届高考英语二轮复习书面表达限时测验：4（含解析）

★ 四川省2016届高考英语一轮复习课时作业（25） Module 1 British and American English 外研版必修5

★ 2017届高考英语二轮复习大题冲关秘籍完形填空之夹叙夹议文：应试策略（含解析）

★ 【课堂新坐标】2017届高考英语（通用版）二轮复习书面表达专题训练：训练6 议论文＋记叙文（含解析）

★ 【北师大版】2014届高考英语一轮复习指导课时作业：Unit 8 A卷 Word版含解析

★ 四川省广安市2014高考英语一轮基础训练题（9）及答案

★ 2017届高考英语二轮复习课时训练：5（含解析）

★ 重庆市2014高考英语阅读理解一轮（精品）训练题（7）附答案

★ 2017届高考英语二轮复习大题冲关秘籍完形填空之记叙文：体验真题（含解析）

★ 湖南省汝城二中2014届高考英语一轮复习阅读训练 (66)