A radioactive substance emits a particle from the nucleus of one of its atoms. The particle consists of two protons and two neutrons. What is the name of this process?
【单选题】Topic 26 Session 1 4-1 Read the sentence pairs. Choose which word or phrase best fits each blank. 1-B A ____________________ is an observable occurrence.
【单选题】Topic 26 Session 1 4-1 Read the sentence pairs. Choose which word or phrase best fits each blank. 1-A A ____________________ is caused by a human error in coding or input.