The molecules which form the bilayer region of the cell membrane have hydrophilic regions on the outer surface and hydrophobic regions on the inner surface.

The answer is: phospholipid molecules

Explanation:

The plasma membrane of a cell is consists of a lipid bilayer. This lipid bilayer, also known as the phospholipid bilayer, is a polar membrane composed of two layers of lipid molecules, usually amphipathic phospholipid molecules.

The amphipathic phospholipid molecules have a hydrophilic phosphate head on the exterior and a hydrophobic tail consisting of fatty acid chain on the interior of the membrane.

when the volume of gas is   changed from   717.73 ml   to 852 ml   the temperature will   change   from 315   c to 452   c

    calculation

this is calculated using the charles law formula

that is,   v1/t1 = v2/t2

          v1=?

        t1 = 315 c   into   kelvin = 315 +273 = 588 k

        v2 = 852   ml

        t2 = 425c + 273 =698 k

make v1   the subject of the formula ( by   multiplying both side by t1)

  v1=( v2 xt1) / t2

v1= (852 ml   x 588 k)/ 698 k= 717.73 ml