Final answer:
One major factor that determines whether a molecule can transport through a cell membrane is size.
Step-by-step explanation:
One major factor that determines whether a molecule can transport through a cell membrane is size. The cell membrane is selectively permeable, meaning it allows only certain substances to pass through. Small molecules can easily pass through the cell membrane, while larger molecules are often unable to cross it.
Learn more about Factors affecting molecule transport across cell membranes