Final answer:
C. Phospholipids are the primary building blocks of the cell membrane, forming a bilayer that constitutes the membrane's basic structure. They are accompanied by proteins, carbohydrates, and cholesterol that all play crucial roles in membrane function and structure.
Step-by-step explanation:
The molecules that are the basic building blocks of the cell membrane are phospholipids. Phospholipids have a unique structure consisting of a hydrophilic ('water-loving') head and two hydrophobic ('water-fearing') tails. This structure allows them to form a bilayer that serves as the fundamental architecture of the cell membrane. Other important components of the cell membrane include proteins, carbohydrates, and cholesterol. Proteins are integral to the cell membrane's function, including acting as transporters, while carbohydrates are often attached to proteins or lipids, playing a role in cell recognition and adhesion. Cholesterol contributes to the membrane's fluidity and flexibility.