Answer
Complex barrier to the flow of substances out of the cells,and restrictions to inflow of unwanted substances into the cells. The hydrophobic and hydrophilic nature of the cell membrane controls the entry of substances from the extracellular medium into the intracellualr. In addition the polarity restricts certain substance movement across the walls.
Serve as the selective channels for the influx of certain substances into the cells, and the out flux of wastes.This is through ion channels for the movements of ions across.
Provide insulation to the cells,to maintain the constant internal temperature,this is through the presence of lipids as( Phospholipids and cholesterol).The latter prevent the clogging of the lipids in the cell membrane therefore preventing frozen up of the cell membrane,providing insulation.
Separation of metabolic process in the cell.
Explanation:
Cell membrane-This is present in all cells.But the variation of its constituents makes it unique to each cell. Although it performs the same role, the location and role the cells it bounded, reflects its constituents, it is made up of lipids, carbohydrate, protein and cholesterol
The answer is A
Using energy
I believe the answer is decomposers. Does that make sense in the context of what you have learned in class? If you look up "the circle of phosphorous," you can see images that show that decomposers, like fungi and microbes break down dead animals and plants using some of their phosphorous, but what isn't used is returned to the soil. The same can be said for sulfur. Decomposers like fungi and bacteria break down dead plants and animals and return sulfur to the soil.
I want to warn you that there is a slight possibility that I might be incorrect. I am still pretty sure I am right. The only thing that makes me question the correctness of my answer is another brainily question I saw when i was looking up this stuff. Two people had responded to that Middle schoolers question and had said the answer was producers. They didn't give any explanation for their answers. So, I am confused as to how they both got the same answer that was different from mine. No material that I have seen regarding either the phosphorous cycle or sulfur cycle has shown plants as RETURNING the most sulfur and phosphorous into the soil. Usually, it has been depicted that producers, such as plants, UTILIZE the most phosphorous and Sulfur from the soil.
