If your idea of a good time is to sleep in a hut, carry your own rubbish, and eat insects and wild animals, then ecotourism may be just for you. But is it also for people who want to fly over a rainforest sky before checking into a comfortable and expensive hotel in the middle of a national park? Whatever ecotourism is, it is hot--perhaps too hot for its own good. The World Tourism Organization claims that the industry looked after 592 million travelers last year who spent $423 billion, and of all the types of tourism, ecotourism seems to be the fastest growing. By the broadest measure -- a trip with some sort of nature or wilderness element -- ecotourism already accounts for perhaps a third of these travelers. On a stricter definition favored by the Ecotourism Society, it is "responsible travel that preserves natural environments and keeps up the well-being of local people," which accounts for no more than 5% of tourism. Ideally, ecotourism helps both people and nature. Before the disastrous civil war, Rwanda's Mountain Gorilla Project was one such model. Visits to the gorillas were limited, local guides ensured good behavior or on the part of the humans, and the high admission charge - $170 a day -- paid for salaries and presentation of the gorillas' living areas. As this made the gorillas worth more alive than dead, poaching   decreased. As another example, preservation Cooperation, Africa's largest ecotour operator, uses only local labor, buys products 5om local farmers, and supports building projects: such as clinics and schools. This contribution to social advance is also good business sense. Projects from which local people benefit directly are less likely to be affected by poaching and theft. Ecotourism's biggest problem is labeling. Going on an eco-tour is no guarantee of good ecology. So far, only Australia has an official system to grade tour operators and tourist attractions on the basis of their "greenness". Another issue is how eco-tourists damage the environment. Dolphin-feeding, for instance, is innocent and enjoyable, but after too many free meals, the dolphins forget how to catch their own dinners. Keeping prices high is one way to limit enthusiasm. But measuring the effect of ecotourism on human environments is trickier. It is common, for villagers to see ecotourism as a source of new income. Hence, the very tourists who venture in search of traditional cultures end up breaking them up. As ecotourism becomes more popular, it will finally threaten the very things that are good for business. Within the tourism industry as a whole, ecotourism   _  .
has no single, clear definition that would satisfy everybody has expanded less rapidly than other types of tourism claims that no comfortable hotels should be used by tourists most often has a negative effect on local culture
Question: If your idea of a good time is to sleep in a hut, carry your own rubbish, and eat insects and wild animals, then ecotourism may be just for you. But is it also for people who want to fly over a rainforest sky before checking into a comfortable and expensive hotel in the middle of a national park? Whatever ecotourism is, it is hot--perhaps too hot for its own good. The World Tourism Organization claims that the industry looked after 592 million travelers last year who spent $423 billion, and of all the types of tourism, ecotourism seems to be the fastest growing. By the broadest measure -- a trip with some sort of nature or wilderness element -- ecotourism already accounts for perhaps a third of these travelers. On a stricter definition favored by the Ecotourism Society, it is "responsible travel that preserves natural environments and keeps up the well-being of local people," which accounts for no more than 5% of tourism. Ideally, ecotourism helps both people and nature. Before the disastrous civil war, Rwanda's Mountain Gorilla Project was one such model. Visits to the gorillas were limited, local guides ensured good behavior or on the part of the humans, and the high admission charge - $170 a day -- paid for salaries and presentation of the gorillas' living areas. As this made the gorillas worth more alive than dead, poaching   decreased. As another example, preservation Cooperation, Africa's largest ecotour operator, uses only local labor, buys products 5om local farmers, and supports building projects: such as clinics and schools. This contribution to social advance is also good business sense. Projects from which local people benefit directly are less likely to be affected by poaching and theft. Ecotourism's biggest problem is labeling. Going on an eco-tour is no guarantee of good ecology. So far, only Australia has an official system to grade tour operators and tourist attractions on the basis of their "greenness". Another issue is how eco-tourists damage the environment. Dolphin-feeding, for instance, is innocent and enjoyable, but after too many free meals, the dolphins forget how to catch their own dinners. Keeping prices high is one way to limit enthusiasm. But measuring the effect of ecotourism on human environments is trickier. It is common, for villagers to see ecotourism as a source of new income. Hence, the very tourists who venture in search of traditional cultures end up breaking them up. As ecotourism becomes more popular, it will finally threaten the very things that are good for business. Within the tourism industry as a whole, ecotourism   _  .
A. has no single, clear definition that would satisfy everybody
B. has expanded less rapidly than other types of tourism
C. claims that no comfortable hotels should be used by tourists
D. most often has a negative effect on local culture
Answer: