In the nuclear reaction $_2He^4 + _zX^A \to _{z+2}Y^{A+3} + A$,$A$ denotes:

The nuclear cross-section is measured in barn,it is equal to

If $r_1$ and $r_2$ are the radii of the atomic nuclei of mass number $64$ and $125$ respectively,then the ratio $(r_1/r_2)$ is

Which is the correct unit for measuring nuclear radii?

An atom of mass number $15$ and atomic number $7$ captures an $\alpha$-particle and then emits a proton. The mass number and atomic number of the resulting product will respectively be

$STATEMENT-1$: The plot of atomic number ($y$-axis) versus number of neutrons ($x$-axis) for stable nuclei shows a curvature towards the $x$-axis from the line of $45^{\circ}$ slope as the atomic number is increased.
$STATEMENT-2$: Proton-proton electrostatic repulsions begin to overcome attractive nuclear forces in heavier nuclides,requiring more neutrons to maintain stability.