Usually, your thesis should use as much of the wording of the question given as possible. If you are writing a thesis on a core AOS , there would be a rubric in which you then have to use as many points relevant from the rubric and the question and incorporate it into a thesis. A thesis can be simple at times and complex , it is really up to you how you feel when it comes to writing a thesis. A thesis is usually 1 or 2 lines. With a topic sentence, you always have to relate it to your thesis and be simple and concise. You shouldn't go around the idea you want to talk about, as it is just unnecessary at times and usually a simple topic sentence that is straight forward and explains the key ideas is better. I usually would have 2 sentences for a topic sentence as such I have the 1st sentence bring up the idea and the 2nd sentence to elaborate of as my teacher says it ''give life to it'' and further refine the idea. That's how I do it , you can experiment and find your own method when it comes to it