GRE Reading Comprehension: ETS-GRE阅读ETS - 44F2Y26U1OI4TDZG7

In the passage, the author is primarily concerned with A. presenting a hypothesis and describing compelling evidence in support of it B. raising a question and describing an important discovery that led to an answer C. showing that a certain genetically caused disease can be treated effectively with drugs D. explaining what causes the genetic mutation that leads to heart disease E. discussing the importance of research on animals for the study of human disease