C, because it protects the cell from the outside environment
Answer is: the part of an experiment that stays the same though out the experiment is constant.
<span>Constant is a quantity that does not change.
</span>Experimental variable<span>, which is the also part of an experiment, is affected by the experiment (have change).</span>
Glucose is what the citric cycle uses to create energy for our cells in the form of ATP
Earths elliptical orbit around the sun with winter occurring when the earth is far away from the sun and summer is closest to it how ever our planets distance from the sun has a little effect on the onset of seasons
hope this makes sense if not just message me and ill try to put it in a more understanding way :)
They use a method called spectroscopy.
