Can you name an animal whose killing cannot be performed without spilling your own blood?

How is the moon similar to a dollar?

What can jump higher than a building?

What 5-letter word typed in all capital letters can be read the same upside down?

Rearrange the letters in "new door" to make one word.

Decode this picture on T-Shirt and tell what it says ?

What has hands, but can’t clap?

How can a man go eight days without sleep?

Buy me, smell me or deliver me, I do not change.

Who am I?

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 paper it was a blank sheet of paper with a solitary question on it: 'What is the 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?