Answer the following question given this paragraph: 

Radioactive decay involves the emission of a particle and/or energy as one atom changes into another. In most instances, the atom changes its identity to become a new element. There are four different types of emissions that occur.


Q: What involves the emission of a particle and/or energy as one atom changes into another?

 Choices:

- spontaneous mutation

- atomic transformation

- enthalpy

- radioactive decay

A:
radioactive decay
