Using this illustration as a guide, indicate the level one would need to drill to gain a sample containing the highest ratio of parent rock in comparison with organic material. horizon C

horizon A

horizon B

horizon O

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 -

it’s lava came from an explosive eruption

the correct answers are;

a. the rock was made from more than one type of material.

e. layers of hot liquids in the rock cooled and solidified at different temperatures.

these are the two options that are related to the statement given above.