Lipids are not polymers because they contain one molecule and are not macromolecules.
Carbohydrates attached to lipids and to proteins extend from the outward facing surface to the membrane. The second factor that leads to fluidity is the nature of the phospholipids themselves
I believe passive transport is a form of diffusion. And it doesn't require any energy unlike active transport.
Answer:
This question appears incomplete but The correct option is the last option
Explanation:
Cell membranes are made up of a lipid/phospholipid bilayer in which each layer consists of an hydrophilic head (water loving) and a hydrophobic tail (water fearing). The hydrophobic tail of each layer is oriented inward and the hydrophilic heads are oriented outward so the cell can interact with water molecules inside (the cytoplasm) and outside the cell environment. This orientation forms a critical part of the function of the cell membrane that makes it a selectively permeable barrier that regulates what goes in and out of the cell.
