What are two methods in which nitrogen fixation can occur?

the relative standard reduction potential of the half-cell in which reduction occurs; more positive than the other half-cell. reduction is a chemical process in which electrons are added to an atom or an ion; it always occurs accompanied by oxidation of the reducing agent.

it would be heredity

it's diluted or concentrated

in a diluted solution, you can add a lot more solute but in concentrated only a little more can be added