2. which action is prevented by the cell membrane? a. unlimited flow of heat into or out of the cellb. the flow of oxygen into or out of the cellc. the flow of light into or out of the celld. unlimited flow of water into or out of the cell

D. Unlimited flow of water into or out of the cell Let's take a look at the options and see what does and does not make sense about what the cell membrane prevents. A. Unlimited flow of heat into or out of the cell * Preventing the flow of heat requires insulation and generally, the thicker the insulation and less material used in the insulation improves its capability. Cell membranes are entirely too thin and have too much mass for their size to be an effective thermal insulator. So this is a bad choice. B. The flow of oxygen into or out of the cell * I hope this is obviously wrong. If oxygen couldn't get into the cell, then life as we know it wouldn't exist. Our biology requires oxygen in order for our metabolism to work. So this too is a bad choice. C. The flow of light into or out of the cell * Go outside during the day and hold your hand between your eyes and the sun. Do you see anything through your hand like perhaps a reddish color? If so, that's a pretty solid demonstration that light can pass through the cell membrane. So this too is a bad choice. D. Unlimited flow of water into or out of the cell * Now we're getting somewhere. Water does need to pass through the cell membrane, but we can't have unlimited flow. The cell needs to have a proper balance of molecules suspended in water inside. Too much water is bad, too little water is also bad. The cell membrane helps regulate the water content within the cell, so this looks like the only good choice.