Scientists have long debated what killed the non-avian dinosaurs. One theory involved massive volcanic eruptions in India. A geologist set out to test if volcanoes alone could do it. Using a climate simulation model, she input the data for the gases released by these eruptions. The model showed that the temperature changes would have been too gradual to cause a mass extinction. This led her to conclude that volcanoes likely weren't the sole cause.
Which choice best states the main purpose of the text?
To describe a study that casts doubt on a specific hypothesis
To prove that asteroids definitely killed the dinosaurs
To explain how climate simulation models work
To argue that dinosaurs are not actually extinct
Correct Answer: A
Choice A is the best answer. The text introduces a hypothesis (volcanoes), describes a test, and concludes the hypothesis is likely wrong (volcanoes weren't the sole cause).
Choice B is incorrect. Asteroids aren't mentioned. Choice C is incorrect. The model is a tool, not the main topic. Choice D is incorrect. It discusses extinction causes, not survival.