If the model shows a substance crossing a cell membrane then the following that describes the process is a. The model shows the process of active transport because the solute particles are moving from an area of low concentration to an area of high concentration.
Active transport refers to the movement of particles in a semipermeable membrane from outside the cell to inside in a process that requires energy to carry out this movement.
Active transport uses the energy provided by the hydrolysis of adenosine triphosphate, commonly known as ATP.