Fission reactions are induced in nuclear power plants because they produce great amounts of energy. Often, a nucleus must be forced to undergo fission by being hit by another particle. A U-235 nucleus being hit with some other particle causes it to undergo fission and emit more particles. Those particles eventually hit other U-235 nuclei, which propagates the reaction. What is this type of reaction called

Chain reaction

Explanation:

A chain reaction is a reaction that sustains itself. It has the ability to continue for a very long time without adding any more materials to the reaction system. It may be succinctly described as a self propagating reaction.

In a nuclear fission, uranium-235 is bombarded with neutrons to produce unstable uranium-236 which disintegrates to form daughter nuclei and produce more neutrons that bombard more uranium-235 and the reaction continues indefinitely.

metals are good conductor of electricity. it has free electrons on their surface. according to electron pool theory, each atom present in a metal crystal losses all of its valence electron and as a result a pool of free is form. these pool of electrons are free to move and   conduct electricity easily   while making metal as good conductor.

the correct answer is a. the ability of electrons to flow throughout the metal.

if it's not useful, feel free to report for mistake in answer.