Which of the following us an example of an open system?
an aquarium with both pants and animals
an enzyme found in deep ocean organisms that allows them to grow
a living single celled organism like phytoplankton
a river that has been dammed

what school and grade?

the solute can move "downhill," from regions of higher to lower concentration, relying on the specificity of the protein carrier to pass through the membrane. this process is called passive transport or facilitated diffusion, and does not require energy.