What is an effector?
a. a molecule that brings about a cellular response to a signal.
b. a molecule that brings a signal to a cellular response.
c. a molecule that brings enzymatic changes to a cell.
d. none of these is the correct answer.

The correct answer is a A molecule that brings about a cellular response to a signal.

Explanation:

Effector molecule is a small molecule that act as ligand to generate various cellular response by binding with target proteins(receptors).

  Effector molecules can regulate catalytic activity of enzymes,gene expression and various signaling processes that are very much important for proper functioning of the cell that the effect molecule target.

 Examples Allosteric effectors which can be either modulators or inhibitors depending on the nature of the effector molecule.

explanation:

metals have excess of electrons whereas non-metals have deficiency of electrons. thus, in order to gain stability metals easily donate their electrons to the non-metals.

for example, electronic configuration of sodium is and electronic configuration of phosphorous is .

when a phosphorous atom and sodium atom combine together then sodium will donate is extra one electron to the phosphorous atom. as a result there will be formation of ionic bond between sodium and phosphorous.

the reaction will be as follows.

there, are three sodium sodium atoms and each of them will donate its one extra electron to phosphorous atom. thus, the sub-shell of phosphorous gets completely filled.  

thus, we can conclude that electrons are transferred from atoms of sodium to atoms of phosphorous. this transfer makes the sodium atoms donate one electron and the phosphorous atoms to gain one electron. as a result, the sodium and phosphorus atoms strongly attract each other.

the positions which points up in upward carbon and down in downward carbon are axial

and vice versa holds true for equatorial positions

so the correct answer with labelled diagram will be