How does helium nucleus stability show nuclear force saturation?

[GD_Green]

I have solutions to a past paper essay question that indicates that the student should explain the saturation of the nuclear force in terms of the stability of the helium nucleus. I do not see how to do this, I can only explain the saturation of the force in that the nuclear biniding energy is proprtional to A, not A squared.
So, how does the stability of the helium nucleus indicate the nuclear force is saturated?

 

[OlderDan]

I have solutions to a past paper essay question that indicates that the student should explain the saturation of the nuclear force in terms of the stability of the helium nucleus. I do not see how to do this, I can only explain the saturation of the force in that the nuclear biniding energy is proprtional to A, not A squared.
So, how does the stability of the helium nucleus indicate the nuclear force is saturated?

This might be of some help

http://www.applet-magic.com/semiempirical.htm

At a fairly simple level, I think the stability of the helium nucleus is an indication of saturation because there are no stable nuclei with 5 nucleons, indicating that there is not enough force to bind and additional nucleon to a helium nucleus. Hence, saturation

 

[GD_Green]

Thank you very much.