when i answer a question and submit it why does edit and delete appear?

You cant make Edit and Delete disappear.

Edit button will help you to change your answer, while you also have the option of deleting an answer if you so please.

If you dont like these options, dont use them :)

You can use the "edit" button to add or change something in your answer.

"Delete" button is just for that --deleting your answer if you want.

This gives you one more chance at changing your answer or adding to it.