What is used as a moderator in a nuclear reactor?

$A$ $^{235}U$ nuclear reactor generates energy at a rate of $3.70 \times 10^7 \text{ J/s}$. Each fission liberates $185 \text{ MeV}$ of useful energy. If the reactor has to operate for $144 \times 10^4 \text{ s}$, the mass of the fuel needed is (Assume Avogadro's number $= 6 \times 10^{23} \text{ mol}^{-1}$, $1 \text{ eV} = 1.6 \times 10^{-19} \text{ J}$) (in $\text{ kg}$)

By which process is the energy released from the Sun?

Two deuterons undergo nuclear fusion to form a Helium nucleus. Energy released in this process is ............. $MeV$ (given binding energy per nucleon for deuteron $= 1.1 \, MeV$ and for helium $= 7.0 \, MeV$)

Nuclear fission experiments show that neutrons split uranium nuclei into two fragments of about the same size. This process is accompanied by the emission of several:

This question contains Statement-$1$ and Statement-$2$. Of the four choices given after the statements,choose the one that best describes the two statements.
Statement-$1$: Energy is released when heavy nuclei undergo fission or light nuclei undergo fusion.
Statement-$2$: For heavy nuclei,binding energy per nucleon increases with increasing $Z$,while for light nuclei,it decreases with increasing $Z$.