The sentence is that 8 other questions written answers including an opinion essay.
So what's the opinion essay.
Is it a investigation which we shoud write some personal information or a small composition to show our view.
A favor to ask, first of all. When you say "The sentence is..." could you actually separate the sentence so that it's not part of the introduction. I can't really tell what your sentence is. (Example: "The sentence is: My dog has a bone." Thanks.
I would think an opinion essay is an essay based on your personal opinion of a subject, rather than one based on facts that can be confirmed.
Just to add to Copyright's response, I performed a google search of "opinion essay" and discovered that:
1) "An opinion essay is a formal piece of essay writing which presents the author’s point of view on a particular subject supported by reasons and examples. The opposing viewpoint is also suggested." [Source]
and 2) You being by stating..."your personal opinion on a topic of your choice" and "you are required to proceed with arguments that explain and justify your position." [Source]
I hope that helps. Although, I am quite sure that Copyright's explanation was sufficient!