During diffusion, when the concentration of molecules on both sides of a membrane is the same, the molecules will (1 point).
a. move across the membrane to the outside of the cell..
b. stop moving across the membrane..
c. continue to move across the membrane in both directions..
d. move across the membrane to the inside of the cell.

I think the correct answer from the choices listed above is option B. During diffusion, when the concentration of molecules on both sides of a membrane is the same, the molecules will stop moving across the membrane. This is because equilibrium has already been achieved and there is no more driving force which is the concentration gradient present.

We can use solar powered cars or ride bikes instead of cars that burn fossil fuels

C- a hypothesis or d- an observation