Answer:
A trail, a union, together tied. Come across me and you will find you cannot change the course I'm on. Without me you cannot travel on. What am I?
I am used for light yet I am solid. Without me you would feel enclosed. I hate being touched especially with a lot of force. I like to be in buildings.
I am always around you but often forgotten. I am pure and clean most of the time, but occasionally rotten. What am I?
I am an activity dogs are very good at when a ball is thrown.
I soar without wings I see without eyes. I've traveled the universe to and fro. I've conquered the world yet I've never been anywhere but home.
I am a rock group with four members. All dead one was assassinated.