Mountains are tallest true or false

Question: What's higher than mountains, Smaller than trees?

Question: How do you stop a dog barking in the back seat of the car?

Question: Can you make VI out of IX?

Question: What tastes better than it smells?

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

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?