Diagram below shows a portion of the geologic time scale.

Which of these is the most likely inference that can be drawn from the time scale?

A. Microscopic life appeared on earth before flowering plants.

B. Microscopic life appeared on earth before rocks were formed.

C. Flowering plants appeared on earth before oxygen was formed.

D. Flowering plants appeared on earth before land animals were created.

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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correct answer is a. and d.

1. b.

2. d.

3. a.

5. d.

6. c.

these are the only ones that i know, i hope this , and good luck.