GRE Reading Comprehension: JiJing 352-GRE阅读机经352篇 - 82B17CK771QFWZDRJ

According to the passage, a true double nucleus may be produced by the A. collision of two dwarf galaxies B. incorporation of a dwarf galaxy into a larger galaxy C. merging of two galaxies of approximately equal size D. separation of a single nucleus into two parts by a lane of dust E. waves of new star formation resulting from an instance of galactic cannibalism