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?
What goes up a chimney down but can't go down a chimney up?
I am the same written forward backward and upside down.
What is the difference between a poorly dressed man on a bike, and a well-dressed man on a unicycle?
What do you get when you cross a pig with a karate expert?
Runs over fields and woods all day. Under the bed at night sits not alone, With long tongue hanging out, Resting at your feet until we go for a walk