Decapitate me

Question: Decapitate me and all becomes equal. Then truncate me and I become second. Cut me front and back and I become two less than I started. What am I?

Question: What do you call a sad bird?

Question: What can be broken but never forgotten?

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?

Question: What tastes better than it smells?

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