Why is uranium-235 able to undergo a chain reaction while many other nuclei cannot? a.The energy produced is enough to heat the remaining uranium-235 to the point of fission, initiating and maintaining a chain reaction. b.Repetitive positron emission from uranium-235 combines with electrons of nearby uranium-235 atoms to induce a chain reaction. c.The krypton and barium atoms generated are themselves prone to undergoing fission. d.Uranium-235 fission generates three neutrons from one atom, and each neutron can start fission in another uranium-235 atom.