阅读下列短文，根据短文内容填空，在未给提示词的空白处仅填写1个适当的单词，在给出提示词的空白处用括号内所给词的正确形式填空。

Billions of poor people around the world 【小题1】 (depend) on the use of wood for cooking. And as they take more and more firewood from wild areas, they are destroying habitats around the world. Wood collection is one reason why many animals have become endangered. This is 【小题2】 Dr. Metcalf spends each summer in Africa. He wants to teach women and children in villages how to cook with the sun. He helped create Solar Cookers International. It’s an organization 【小题3】 introduces solar cookers to developing countries as well as teaching people how to use them.