In a nuclear fission reaction, a freely moving neutron is introduced to a nuclear fuel, then a neutron is absorbed by an atom's nucleus.
Nuclear fission is a process in which an unstable nuclei will convert into stable nuclei after releasing the energy in the form of particles.
When we introduce a freely moving neutron to the nuclear fuel of uranium-235 nuclei then this introduced neutron was absorbed by the nuclei and makes the nuclei more unstable. Then this unstable nuclei will convert into two nuclei in the addition of three neutrons.
Hence, a neutron is absorbed by an atom's nucleus.
To know more about nuclear fission, visit the below link:
https://brainly.com/question/14019172
#SPJ1