TOEFL Listening: ETS-TOEFL听力机经 - IFF1JFHY451G1CX6P$

Why does the professor mention that newborn stars are surrounded by disks of dust and gas? A. To describe a method for testing two theories about brown dwarfs B. To clarify how brown dwarfs are drawn into star systems C. To emphasize that brown dwarfs move at low velocities D. To introduce planet formation as the topic of the next lecture