Which path through the carbon cycle is possible?
a. plant ® atmosphere ® animal
b. animal ® plant ® atmosphere
c. plant ® animal ® atmosphere
d. atmosphere ® animal ® fossil fuel

C. plant ® animal ® atmosphere

Explanation:

Carbon cycle is one of the important biogeochemical cycles on earth. The plants absorb the atmospheric carbon dioxide required for the process of photosynthesis. These plants convert the reactants into products of carbohydrates. These carbohydrates and other plant products are consumed by the animals. When animals die the accumulated organic matter containing carbon as a component get decomposed by the soil microbes. After decomposition the carbon dioxide gas from the soil released into the atmosphere.

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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