Riddle #1206

Question: 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?

Question: What do you call a sad bird?

Question: What tastes better than it smells?

Question: What goes in the water black and comes out red?

Question: What loses its head in the morning and gets it back at night?

Question: What two things can you never eat for breakfast?