1. The main gas causing the greenhouse effect. a. dust / b. oxygen carbon dioxide
2. Collecting paper and plastics so they can be used again. a. recycling / b.cycling collection
3. The main actions of companies like Greenpeace and WWF: a. criticize/ b. warn make fun of
4. A plant or animal that is having trouble living in a certain place and may disappear soon. a. extinct species b. threatened species c. endangered species
