Which environmental changes occur fast a. global warming b. oil spill c. pond succession d. changing seasons

Oil spill occurs quickly. It only takes an instant for an oil spill to occur, while global warming, pond succession, and changing seasons happen over years or months

Hope this helped!

~Just a girl in love with Shawn Mendes

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 -