Answer is: 1) nuclear, and energy is released.
Missing question:
1) nuclear, and energy is released.
2) nuclear, and energy is absorbed.
3) chemical, and energy is released.
4) chemical, and energy is absorbed.
Missing reaction: n° + 92/235U → 52/137Te + 40/97Zr + 2n°.
This is nuclear reaction, because nucleus of an atom (in thus example uranium-235) and a subatomic particle neutron from outside the atom collide and produce two nuclides (tellurium-137 and zirconium-97) that are different from the nuclide that began the process and two netrons are released.
