A cell in an embryo that still resembles the original cells of that embryo but will eventually form the spinal cord is ___.

 Determined only

Explanation:

The determination of different cell types such as cell fates implies progressive restrictions on their development potential. When a cell "selects" a particular destination, it is said to be designated, although it still "looks" like its indefinite neighbor. The determination implies a stable change: the fate of the particular cells does not change.

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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