Riddle #1013

Question: I am a digit, but two of the ten.
Two of me make a promise.

What am I?

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?

Question: What do you call a sad bird?