Why do you think Flourine is able to pull the electron away from Lithium?

It is more electronegative

Explanation:

Fluorine is able to pull the electron away from Lithium because it a more electronegative specie.

Electronegativity is a measure of the relative tendency with which the atoms of the element attracts valence electrons in a chemical bond.

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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the menstrual cycle – higher tier. negative feedback mechanisms affect the production of hormones in the menstrual cycle. oestrogen also stimulates the release of lh (luteinising hormone) from the pituitary gland, which in turn controls the production of progesterone.