A wounded animal will fight like a maniac, relentless, savage and murderous. Fight (reciprocal) To contend in physical conflict with each other, either singly or in war, battle etc. The two boxers have been fighting for more than half an hour. Fight (intransitive) To strive for something;...
In the framework of the Standard Model, the fact that proton and neutron have nearly the same mass is explained as consequence of an approximate symmetry: isospin [1]. The symmetry is broken explicitly because the two lightest quarks neither have the same charge nor the same mass. The violat...