Complete the statements by writing the number from the graph. The substance is in the gas phase only in region . The substance is in both the liquid and the solid phase in region . The substance is in only the liquid phase in region . The melting point is the temperature at region . The boiling point is the temperature at region .

The correct answer is c

Pretty sure it's d. heterogeneous is separated by physical properties. 

Vander waals forces are inter molecular bonds that exist within molecules of the same substance. a water molecule is made up of oxygen and hydrogen atoms which share electrons between each other. the vander waals forces are forces that exist between multitude of different  molecules of water. dipole dipole forces is the type of vander waals force that exist in water. the oxygen atom which is more electronegative pulls the shared electron closer to itself thus generating a partial negative charge while the hydrogen acquire a partial positive charge. these two different charges causes attraction to occur in water molecules.