The plasma membrane is composed of a phospholipid bilayer with embedded proteins what is one of the functions of the embedded proteins

Transport proteins (carrier proteins and channel proteins) allow substances into and out of the cell that cannot pass through the phospholipid bilayer (as they’re either to large, charged or not lipid soluble) by facilitated diffusion.
Specifically channel proteins allow ions into and out of the cell by creating a pore in the membrane in which they can move through with their concentration gradient

Its either a) or b),wind and water erosion gradually widen the canyon

ypc