"La carretera" should be the answer. It is the only one that makes sense.
1. Bicicleta
3. No apagar las luces de tu casa, cuando no la usas.
4. No tala de árboles. No quemar cosas.
5. Recoger basura o no tirar basura en los parques.
6. Tirar basura en los ríos.
I’m not sure what exactly you needed to do. I guessed you needed to put an example to each statement.
I hope this helped you.
If it didn’t, you let me know, please.
