I think the correct answer is A
The cell membrane allows this to be true
Answer:
Facilitated Diffusion
Explanation:
Some molecules can move down their concentration gradients by crossing to the lipid portion of the membrane directly,while others must pass through membrane protein s in a process called Facilitated Diffusion
Hypotheses must be provable. If scientists cannot prove a "hypothesis" right or wrong, they need to change it to a legitimate hypothesis - something you can prove.
If it is proven wrong, they can change certain aspects of it to make a more specific experiment.