增加：在缺词处加一个漏字符号（∧），并在其下面写出该加的词。

删除：把多余的词用斜线（\）划掉。

修改：在错的词下划一横线，并在该词下面写出修改后的词。

注意：1）每句不超过两个错误；

2）每处错误及其修改均只限一词；

3）只允许修改10处，多者（从第11处起）不计分。

    Wechat is becoming increasing popular. The other day, when I was walking by a food shop, I notice an old woman buying some food. She didn't pay in cash. Instead of, she paid with WeChat. WeChat payment is becoming more and more popular. Why do people like to use WeChat payment? The main reason is because it is simple and convenience. What we need to do are to take out the cellphone, scan the QR code and pay the goods we buy. We don't have to carry wallets with me any longer. WeChat payment, that has changed the way we shop, is created by Chinese. We each should be proud of be a Chinese. It shows to the world that Chinese people are creative.

 如图所示，一只“火烈鸟”在湖边觅食，开始时，鸟的两只脚站立在沙滩上，当它把一只脚抬离沙面时，下面说法正确的是

在人类性别决定中起决定作用的是（　　）