Six glasses are in a row riddle

Question: Six glasses are in a row. The first three are filled with milk and the last three are empty. By moving only one glass, can you arrange them so that the full and the empty glasses alternate?

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: People see through me, but none pass through without killing me. I can be anywhere, and can be seen double or single. What am I?