9. This question is based on the following paragraph. The sentences are numbered to help you answer the question. (1) Earth's crust is made up of relatively rigid plates that ride atop Earth's hot, semiliquid mantle. (2) The plates are called tectonic because they're in constant motion. (3) They can move because Earth's mantle is a very hot and semiliquid fluid called magma. (4) Volcanoes are a result of magma rising up or erupting through a plate, particularly where plate boundaries are moving against each other. (5) Also, when plates slide against each other, causing friction along adjacent plate boundaries, earthquakes frequently occur. (6) Therefore, we often find volcanoes and earthquakes along plate boundaries. (7) Plates may also collide. (8) When that happens, mountain ranges are formed. (9) For example, the collision of the plate carrying the Indian subcontinent created the Himalayan Mountains when it collided with the Asian plate. Which statement about this paragraph is accurate? A. There is no single topic sentence. B. There are no supporting details for the main idea. C. The author uses comparison and contrast to organize ideas. D. The topic sentence is the found in the last line. Mark for review (Will be highlighted on the review page)

First of all, the topic sentence is the first one, the topic is introduced, the author will write about the Earth's crust. The following sentences must then explain facts about it and give important information so that the readers can learn something new and useful. We can see that they do so, the author explains the name, why the plates move, how they do and what things they produce when moving. In sentence number 7 we can see that he uses comparison and contrast to organize his ideas, as he proceeds to explain the differences between a plate movement and a collision. By comparing he can be able to address one topic first and compare it with a second one, following a logical order that helps the reader understand the different aspects of the topic.