Answer:
The lipids and proteins that make up the membrane allow it to be selective about what enters and leaves the cell.
Explanation:
The cell membrane is double membranous which is a phospholipid bilayer. It is selectively permeable to only few substances because of the presence of lipids and integral proteins present in it. While lipid bilayer allows direct entry of only fat soluble substances like steroid hormones, fat soluble vitamins etc., the integral/embedded proteins present in the bilayer in the form of receptors, channels and pumps allow the entry of nutrients, ions, wastes etc. But, entry of some substances like water, glucose etc. hardly pass through the cell membrane.
