Ok the role of the cell membrane in regulating how nutrients are gained and waste products lost.

The cell membranes controls what goes in and out by having protein channels that perform their role accordingly sometimes like funnels and like a pump in different cases.

When a channel open in the plasma membrane it allows molecule to pass through, in this case there is no requirement for energy so it is a passive transport.

Gases and food particles broke down in water must be assimilated and waste or harmful substance and molecules must be remove. For most cells, this type of selective transport of all materials all through the cell must happen through the plasma membrane.

answerlength of time the medication is in contact with the skin(moistur level of the skin) depth of respirations blood supply to the area; all of the above; ///