What part of the chicken has the most feathers?

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?

What does an Island and the letter T have in common?

Which alphabet letter is a question?

I am sure no one can have two things for dinner. what are they?

What has hands, but can’t clap?

What number when divided in half becomes zero?

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

Who am I?

He runs but never walks. Murmurs, but never talks. Has a bed, but never sleeps. And has a mouth, but never eats?

I can write cow in 13 letters.

Can You?