I'm written with two letters

Question: I'm written with two letters, said with one and seen with two.What am I?

Question: How do you spell mousetrap with three letters?

Question: Look at my face, I am somebody. look at my back, i am nobody. 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?