Fusion reaction takes place at high temperature because

On average,how many neutrons are released from the fission of a single $U^{235}$ nucleus?

Which of the following statement$(s)$ is/are correct?
$(1)$ The rest mass of a stable nucleus is less than the sum of the rest masses of its constituent nucleons.
$(2)$ The rest mass of a stable nucleus is greater than the sum of the rest masses of its constituent nucleons.
$(3)$ Nuclear fusion involves the fusion of two light nuclei to form a heavier nucleus.
$(4)$ Nuclear fission involves the release of energy by the splitting of a heavy nucleus.

The binding energy of a deuteron is $2.2 \, MeV$ and the binding energy of $_2^4He$ is $28 \, MeV$. If two deuterons fuse to form a $_2^4He$ nucleus,the energy released is ...... $MeV$.

$A$ neutron strikes a ${ }_{92}^{235}U$ nucleus and as a result ${ }_{38}^{93}Kr$ and ${ }_{56}^{140}Ba$ are produced along with:

Fission of nuclei is possible because the binding energy per nucleon in them