If a person is severely dehydrated, their extracellular fluids will become hypertonic to the intracellular fluid. what do you predict will happen to the person's cells

In hypertonic condition, osmosis will occur. In this case, the fluid will be attracted into the hypertonic solution since it osmotic pressure is higher. This condition can cause the nearby cells losing their water molecule and become shrink.
If it happens for a long time, the concentration of molecule inside the cell will increase since the water is decreased. This will cause the cell undergo lysis.

Well, both latitude and intensity of light affect temperature because, the higher the light intensity, the higher the temperature and since latitude is the measure of how close you are to the equator, then the closer to the equator you are, the higher the temperature is.