12. if an ecologist is looking at how many individual organisms live within a certain population, he or she is studying the population

a. interactions.
b. range.
c. density.
d. dynamics.

The answer would be C or Population Density

C. density.

Explanation:

Population density can be define as the number of individuals of the population of a species living in a particular area over a concerned time. It is affected by the death, birth, immigration and migration of the members of the concerned population.

On the basis of the above description, this can be concluded that the ecologist is looking for the population density.

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.  

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