Answer:
1. By reducing the kinetic energy of diffusing molecules.
2. By making the plasma membrane denser.
Step-by-step explanation:
Diffusion of molecules across a cell membrane is affected by temperature. Diffusion is the passive movement of molecules and is slowed down with reduced temperature. Temperature provides the energy to the molecules to move across the cell membrane. Lower temperature levels would also lower down the energy of molecules.
Reduced temperature levels also reduce the diffusion rate by making the plasma membrane denser. The reduced kinetic energy of lipids and proteins of the plasma membrane makes them pack more closely. The close packing of molecules of the plasma membrane slows down the diffusion rate.