题目

Being Left-handed in a Right-handed World      The world is designed for right-handed people, but a tenth of the population prefer the left.     31    The answer to it remains a bit of a mystery. Since scientists have noticed that left-handedness tends to run in families, it’s assumed that left-handedness has a genetic(基因的)component to it.     32    In fact, identical twins, who share the same genes, can sometimes prefer to use different hands. There are also plenty of theories on what else might determine which hand you write with, but many experts believ今年初，我国部分城市连续出现雾霭天气，PM2.5指数偏高。PM2.5能穿过鼻腔进入肺部，甚至渗进血液，危害人体健康。请问： （1）PM2.5入肺的通道：鼻→           → 喉→气管→支气管 （2）PM2.5通过肺泡后首先到达人体心脏的           ，随后经过           （选填“体”或“肺”）循环到达组织细胞，危害健康。 （3）远离雾霭，你可以做些什么？（请举一例）