Three processes that occur in cells are described in the box.
• Substances pass through the lipid bilayer of a cell from areas of high concentration to areas of low concentration.
• Substances move through protein channels of the lipid bilayer of a cell from areas of high concentration to areas of low concentration.
• Substances move through the lipid bilayer of a cell from areas of low concentration to areas of high concentration.
These processes are all examples of —
A crossing over
® the migration of genetic material
© selective permeability
D cellular energy