How are nuclear reactions used to meet the world’s energy needs? both fusion and fission are used to generate electricity, but more fission reactors than fusion reactors are in use. fission reactors are used to generate electricity, but fusion is not yet practical enough to be used. both fusion and fission are used to generate electricity, but more fusion reactors than fission reactors are in use. fusion reactors are used to generate electricity, but fission is not yet practical enough to be used.

Nuclear reactions play an important role in providing the energy if properly they are done in a sustainable way. There are two types of nuclear reactions called fission and fission.

In fission reaction we generally follow controlled chain reactions through which one heavy unstable nucleus is split into two light nuclei with the release of energy which is obtained through the mass defect.in this reactions the temperature is just the normal temperature.The heavy nucleus after  absobing the thermal neutron becomes more unstable and splits.

one can take an example of Uranium-235 .It will split into krypton and lead with the the release of energy .Here approximately 200Mev of energy is released one one Uranium atom undergoes nuclear fusion.

In case of fusion where two light unstable  nuclei combine to form a heavy unstable nuclei with the mass defect converted to energy, a lot of thermal energy is needed.One can say that the temperature  needed for it is equivalent to the temperature of sun

.one can take an example of hydrogen bomb where four hydrogen atom combines to one helium with the release of energy and positrons.In this process approximately 26 Mev of energy is released.but it is not possible on the earth as high temperature is needed for it.

i think the answer is a and b

i wish you luck