If 2 neutrons exert only attractive force, why dont we have a nucleus containing neut

Q. If neutrons exert only attractive force, why don't we have a nucleus containing neutrons alone?

Q. Assertion :It is esay to remove a proton from ${}_{20}^{40}Ca$ nucleus as compared to a neutron Reason: Inside nucleus neutrons are acted on only by attractive forces but photons are also acted on by repulsive forces

Q. Assertion :Two protons and two neutrons are each separated by a distance of $r={10}^{-14}$ m which is the size of the nucleus. Hence the force between two neutrons will be greatest. Reason: At distances of the order of ${10}^{-14}$ m neutrons and protons exert very strong attractive forces on each other and this force does not depend on the charge.

Q. The decay of a proton to a neutron is possible only inside the nucleus. Why?