There is more genetic variation a population that populations.

1. Within

2. Among two different

Explanation:

There is more genetic variation WITHIN a population than AMONG TWO DIFFERENT populations. This is evident in the fact that phenotypic variation occurs at a greater length within a population resulting from natural selection based on survival and the ability to produce offspring strategy. This unlike populations that consist of two or more different populations mingled together.

the answer that best describes the relative refractory period in the neuron is the resting membrane potential is restored, but concentrations of sodium and potassium are not restored to their original state.

the refractory period is the time during which another stimulus given to the neuron will not lead to a second potential. thus, because na+ channels are inactivated during this time, additional depolarizing stimuli do not lead to new action potentials.  

read more on -

you did not attach the discourse, but i assume it to be the discourse on the origin and basis of inequality among men (the original titile in french is: "discours sur l'origine et les fondements de l'inégalité parmi les hommes"), also know as "second discourse". in this discourse, jean-jacques rousseau emphasizes that private property is the basis of all inequalities.

therefore, what enabled the old regime to maintain as long as it did was private property.