人口问题引发环境问题的实质是（   ）

经过飞船搭载的青椒种子返回地面，经研究人员播种后培育出了“太空椒”，其中的决定性因素是（　　）

下列不属于鸟类生殖和发育过程中的繁殖行为的是（   ）

根据短文理解，选择正确答案。

Welcome to the English Corner(英语角)

Room 101

    You can know all about the English Corner here. If(如果) you want to join us, you need to start (开始) from here. The telephone number is 85436200. You can call us.

Room 102

    This room is for oral(口语的) English. All teachers here are from the U.S. You can call 85436210.

Room 103

    The telephone number is 85436220. If you join us, you can read English books here for free(免费). If you do not, you need to pay for your reading.

Room 104

    The room is for English writing from Monday to Friday. You can make friends here.