Answer:
The correct answer is - passive transport.
Step-by-step explanation:
Movement of the protein molecules along the concentration gradient unless both side have become equal in the concentration both side of the cell membrane. This is the example of passive transport.
Passive transport are the transport is a transport of molecule that is along the concentration gradient whcih means from the higher concentration are to less concentration area. Passive transport can be divided in three common types that are - facilitated diffusion, osmosis and diffusion. Protein molecules are transported by the facilitated diffusion.