EVERYDAY SCIENCE

Detailed explanation-1: -As discussed in Chapter 2, the plasma membranes of animal cells contain four major phospholipids (phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, and sphingomyelin), which together account for more than half of the lipid in most membranes.

Detailed explanation-2: -Phospholipids, arranged in a bilayer, make up the basic fabric of the plasma membrane. They are well-suited for this role because they are amphipathic, meaning that they have both hydrophilic and hydrophobic regions.

Detailed explanation-3: -Cell membranes are composed primarily of fatty-acid-based lipids and proteins. Membrane lipids are principally of two types, phospholipids and sterols (generally cholesterol).

Detailed explanation-4: -The fluid mosaic model of the plasma membrane explains that that plasma membrane is composed of a fluid bilayer made of phospholipid molecules, with proteins, glycoproteins, glycolipids and cholesterol molecules embedded in the bilayer. Thus this is the right answer.