Radioactive isotopes that have an excessive neutron/proton ratio generally exhibit

Which of the following can be used for carrying out a nuclear fission reaction?

Consider the following nuclear reactions:
$_{92}^{238}M \to _{y}^{x}N + 2_{2}^{4}He$
$_{y}^{x}N \to _{B}^{A}L + 2\beta^{+}$
The number of neutrons in the element $L$ is:

India conducted an underground nuclear test at

Nuclear fusion produces

The end product of the $(4n + 2)$ radioactive disintegration series is: