The sentence that would best fit at the beginning of a first paragraph and would also make the best topic sentence is: Mammoth hot springs is a popular attraction because the springs are unique. The correct answer would be option D. This sentence is the correct answer because it is the only sentence that introduces the topic.
Answer:
One of the great contributions the Sumerians made to civilization was their many inventions. They invented the first form of writing, a number system, the first wheeled vehicles, sun-dried bricks, and irrigation for farming. All of these things were important for the development of human civilization.