The topic sentence of the following paragraph would be A. Chess is a challenging game that can be a lot of fun once someone learns to play.
Answer:
Animals are used in scientific research to help us understand our own bodies and how they work. This is necessary to develop new medicines. Animals are also used to safety test potential medicines before they are tested in people and to check the safety of other chemicals.
Explanation:
Expository text gets to the point rather quickly. It is intended as education rather than just narrative text. An example of narrative text is the Excerpt by Charles Dickens which is meant to draw a picture of what this woman was like.
So the last one is out.
The first one talks about volcanoes and how they are classified. That's one of your answers if you are trying for brevety and education.
I think the second one would also be a choice. It is trying to show you the nature of anxiety and what causes it. You learn a lot about symptoms from reading it. It's quick and to the point. Expository? Yes.
I don't think four is exactly expository, but I might be wrong. It sounds too argumentative to be completely expository. It wouldn't be my first choice even though I have read Twain a great deal, beginning in my teens. He always has something pointedly funny to say about the human condition. So it's hard for me not to include him in anything. It's not exactly narrative either. The tough ones are three and four.
Three tries to tell you what it would be like to live in another country. I think it likely is the choice you are looking for.
Answers 1,23. I could be wrong, so if you have a different answer in mind, go with it.
A) dealing with workers who know what they’re talking about is more satisfying for clients