阅读下面材料，在空白处填入适当的内容（不多于3个单词）或括号内单词的正确形式。
Ecotourism is a new term in today's tourism industry. Ecotourism, which is considered as a kind of responsible tourism, is ____ (typical) defined (定义) as travel to places ____ special and unusual plants, animals and cultural heritages (遗产) are the main ____ (attract). It takes ecology and culture into consideration. Therefore, programs ____ (concern) the protection of some natural and cultural spots also form a part of ecotourism.
Ecotourism is developing ____ great speed. According to a recent report by the World Tourism Organization, ecotourism in recent years ____(enjoy) an annual growth of about 5% worldwide. More than 80 activities have been listed for ecotourism and ____ include bird watching, hiking, diving, photography and taking part in various kinds of local cultural events.
Big cities are still the major places that attract tourists in our society today. However, it seems some ____ (small) towns and country areas may well become the new destinations for people ____ (visit) tomorrow because they are rich in ecological, cultural and ____ (history) resources.
