What’s the fourth paragraph mainly about?

参考解析：

概括归纳题。根据第四段第二、三句“In addition to their work reducing waste in the cafeteria, the GHS Green Team has also built a garden with flowers and vegetables on campus, and leads cleanups on site and out in the community. Over the years, Randall and his students have also been working on raising money to install solar panels (太阳能板) on the roof of the high school”可知，除了他们减少餐厅废弃垃圾的工作，the GHS Green Team还在校园里建立了有鲜花和蔬菜的花园，兰德尔和他的学生也一直在筹集资金，为了在高中屋顶安装太阳能电池板。因此，第四段主要介绍这个俱乐部组织的活动有哪些。故选C。