我国民间有端午节挂艾草的习俗．艾草含有丰富的黄酮素（化学式为：C₁₅H₁₀O₂），有很高的药用价值．请回答：

小明家菜地里的蔬菜叶色发黄，经检测该地土壤呈碱性．为使蔬菜叶色浓绿，小明根据所学化学知识建议父母购买的化肥是（　　）

几年前唐山市对南部采沉积水区域进行整治，利用地下水同时将西郊污水处理厂中水引入，保证湿地水源，引进湿地植物荷花、芦苇、睡莲、菖蒲等品种，净化水质，为水禽和鸟类创造栖息地，水生生物达到50多种．现已建成唐山南湖国家城市湿地公园，被称为“唐山新增之肺”．请回答下列问题：

（1）聚集在南湖湿地中____ 构成了群落，对南湖进行治理和保护后，该湿地物种丰富度逐渐增加，其群落演替类型为____ ．由于人为因素的影响，群落演替都会按照不同于自然演替的____ 和____ 进行．

（2）湿地生态系统的主要功能包括能量流动、物质循环和____ ．

（3）湿地生态系统能较长时间保持相对稳定，这是因为该生态系统具有____ 稳定性，从生态系统的结构分析，影响其稳定性的因素是____ 

（4）菖蒲对水质有明显净化作用，调查菖蒲的种群密度常用____ 法．

（5）随着南湖生态环境的日益变好，湿地面积不断扩大，吸引了越来越多的鸟类来到南湖繁衍生息，影响鸟类种群密度变化的直接因素包括____ 、____ ．

   What do people do with their old, out-of-date but still useful computers? Most people don't know what to do with them. Many old computers are put away in homes. Many more are simply thrown out with the rubbish.　　
   Some companies are thinking of ways to bring down the number of old computers. Sony has agreed to help recycle old Sony products. Dell, Hewlett-Packard and other companies now also take back some old computers.　　
   In some countries, laws are being passed, too. Computer companies will have to collect and recycle their used products. And 70% of computer waste must be recycled. The idea behind the laws is that computer companies themselves should pay the cost. That will encourage them to make computers that are easier and cheaper to repair and upgrade（升级）.　　
   Yet while many people are throwing away good computers, others cannot afford them at all. Hundreds of organizations are working to solve this problem. They collect and repair old computers. Some also teach others how to repair computers.　　
   The computers then go to schools, charities and people who need them. Giving a used computer to one of these organizations can turn one person's rubbish into someone else’s useful things—and cut down on waste, too.