保护自然环境,维护地球生态系统的平衡,是我们人类共同的目标和任务。那么,什么是生态系统呢?做了下面的试验后,相信你就会明白了。找一个球形烧瓶(医院用过的输液瓶也可以),装入 Protecting the natural environment and maintaining the balance of the Earth's ecosystem are the common goals and tasks of our humanity. So, what is the ecosystem? After the following experiment, I believe you will understand. Find a spherical flask (hospital used infusion bottle can), into