Easy riddles

What goes through a door but never goes in and never comes out?

I'm in you, But not in him, I go up, But not down, I'm in the colosseum, But not a tower, I'm in a puzzle, But not a riddle.

I have just one, but with eight to spare, I am usually friendly, but I sometimes act like I don't care. What am I?

Physicists have built devices to move me very fast. My last seven letters can be commonly found in newspapers, magazines and journals. What am I?

When can you add two to eleven and get one as the correct answer?

I am always hungry and will die if not fed, whatever I touch will soon turn red.

There was once a college that offered a class on probability applied to the real world. The class was relatively easy, but there was a catch. There were no homework assignments or tests, but there was a final exam that would have only one question on it. When everyone received the test it was a blank sheet of paper with a solitary question on it: "What is risk?" Most students were able to pass, but only one student received 100% for the class! Even stranger was that he only wrote down one word! What did he write?

I know a country. If you remove the last aplhabet of its name, it will become a part of your body. Do you?

We can be boring, Or interesting. We can be long, Or short. We can have pictures, Or just words. Many love us, But many also hate us. What are we?

When is your uncle's sister not your aunt?