Answer the following question given this paragraph: 

Nuclear fission is the splitting of the nucleus of an atom into two smaller nuclei. This type of reaction releases a great deal of energy from a very small amount of matter. For example, nuclear fission of a tiny pellet of uranium-235, like the one pictured in Figure below , can release as much energy as burning 1,000 kilograms of coal!.


Q: What do you call the splitting of the nucleus of an atom into two smaller nuclei?

 Choices:

- critical fission

- nuclear fusion

- cell division

- nuclear fission

A:
nuclear fission
