You examine an epithelial cell (skin cell) and notice the chromosomes are visible however it appears there are two nuclei in the cell. What is the best explanation for this observation? a) the cell has just gone through the S –phase of the cell cycle so there is double the amount of DNA
b) the cell has just gone through telophase but not cytokinesis
c) the cell has gone through meiosis I and is preparing for meiosis II
d) the cell is in G1 and is preparing for DNA synthesis

The best explanation if we observe an epithelial cell with chromosomes are visible and two cell nuclei is that the cell has just gone through telophase but not cytokinesis (option b).

Explanation:

A somatic cell, when found in mitosis, exhibits the chromosomes distributed in both poles and the outline of two nuclei in the telophase phase, just before cytokinesis.

In mitotic telophase:

The division and differentiation of the nuclei in telophase is called karyokinesis. Later, cytokinesis occurs, where the daughter cells are separated.

The other options are not correct because:

    a and d. In the other phases described, S and G1, no chromosome distribution is observed at the poles.

    c. A somatic cell does not experience meiosis.

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 -

the relative standard reduction potential of the half-cell in which reduction occurs; more positive than the other half-cell. reduction is a chemical process in which electrons are added to an atom or an ion; it always occurs accompanied by oxidation of the reducing agent.