Riddle #615

Question: The more of me you have, the longer your life.
The more of me you have, the less you have left.

What am I?

Question: What do you get when you cross a witch with sand?

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?