The threshold of excitation ________________.
 | |
 |
is approximately -70 millivolts; |
 |
is approximately - 60 millivolts; |
 |
is approximately +40 millivolts; |
 |
is approximately -80 millivolts; |
 |
not one of the alternatives provided is correct; |
INCORRECT - A correct alternative is provided.
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