The angle of incidence equals the angle of reflection is a statement of the law of

There are  advantages  to being  multicellular  rather than unicellular. these include allowing: the  organism  to be larger.

Ithink its c but im not 100% sure

Na+ loss through sweet plus the dilution has lowered na+ concentration outside of neurons, altering the na+ equilibrium potential. sodium exists more outside the cells than inside. when na+ is lost by sweat plus the dilution( because they drink a lot of water) changes the concentration outside the cell, forcing the water to enter the cell and attempt to balance the concentration inside/outside.the problem is that the abundance of water will cause the cells to swell. most cells can adapt, however, the brain cells can't that's why the runner has confusion and can't control the muscles.  if not treated and this occurs in less than 48 hours, it can be immediately fatal .