一个国家的劳动年龄人口占总人口比重较大，抚养率比较低，为经济发展创造了有利的人口条件，即出现“人口红利”。反之，可能出现“人口负债”。抚养比是指少儿人口（0～14岁）及老年人口（65岁及以上）之和与劳动年龄人口（15～64岁）之比，就业比是指劳动年龄人口与总人口之比。读图，回答问题。

①促进跨时空经济协作→提高资源配置效率→促进产业优化升级

②中小企业经营成本降低→淘汰落后产能→培育经济增长新动能

③网络运营商成本增加→用户网络资费减少→刺激消费拉动经济

④倒逼网络技术革新→ “互联网+”深入发展→数字经济加快成长

水稻成为东南亚主要粮食作物的自然原因是（ ）

As we know, Chongqing has changed a lot. Most of the people feel much safer now. More and more trees are being planted in the city. And every day you can see many old people play sports everywhere. The change makes the people in the city live a happy life. The small survey below is from the people who live in Chongqing. One hundred persons were chosen to answer the questions last week.