A. If they ban swimming with fish, the Great Barrier Reef will be better protected. Tourists should not be allowed to dive very close to the coral reefs.

B. Tourists should always follow the walking paths and trails on the Sapa Trekking Tour. The local people with whom the tourists stay should only use local ingredients. If they only use local ingredients, their carbon footprint will be lower.

D. The boats on the Whale-watching Tour should not get too close to the whales or make too much noise. If the boats are environmentally-friendly, they will not harm the whales or their habitats. This is because environmentally-friendly boats use less fuel and oil, make small waves and are quiet.