Complete the sentences using one of these words: means, series, species.
1. A ... is a group of animals or plants that have the same characteristics.
2. A bicycle is a ... of transport.
3. The bicycle and the car are ... of transport
4. ...She is writing a ... of articles on the ecological state of the region.
5. There are a lot of American TV ... shown on Armenian TV
6. When we were walking on the island we saw many ... of bird