Name 3 some sources of C02.

I am not 100% sure i can't remember but i believe it coal, oil, and natural gas. but I might be wrong.

liquid gas and solid

Explanation:

because you can freeze water you can turn water into gas and you can have it regular

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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b) the inside picture would look at a very high temperature in a very low ph