题目选项分析

As a result of a supernova explosion, every human being on Earth was bombarded on February 23, 1987, by about 100 billion neutrinos; fortunately, neutrinos are harmless elementary particles that are produced in nuclear reactions and that interact very weakly with matter.

As a result of a supernova explosion, every human being on Earth was bombarded on February 23, 1987, by about 100 billion neutrinos; fortunately, neutrinos, which are harmless, are elementary particles produced in nuclear reactions and which interact very weakly with matter.