Fill in the gaps with the words from the box

• untouched

• sustainable

• carbon dioxide

• eco-friendly

• homestay

• carbon footprint

• authentic

• ecosystem

        Jill dreamt of taking an [ ]
        trip to Costa Rica with her friends, Kelly and George. It all started when she became interested in environmental projects, which were aimed at protecting the wildlife. She wanted to learn more about the local [ ] and planned a travel route through the unique places [ ] by tourism. She was fascinated by the idea that they could travel and leave a minimal [ ]. Therefore, they decided not to travel by car because of the [ ] car engine emits.
  

The friends travelled on foot and rented bicycles and sailing boats, slept in tents and in some places stayed with the local families in [ ]. They enjoyed [ ] food, explored the ethnic culture, met and communicated with the locals, watched animals, among which were rare and even endangered species. It was a truly [ ] form of tourism.