What molecule is both hydrophobic and hydrophilic and aggregates as a bilayer to form the fabric of the membrane?

Phospholipids are the molecules that possess both hydrophobic and hydrophilic properties, making them essential for forming biological membranes. Their hydrophilic "head" interacts with water, while their hydrophobic "tails" repel it. When phospholipids aggregate, they arrange themselves into a bilayer, with the tails facing inward and the heads facing outward, creating the structural foundation of cell membranes. This dual characteristic is crucial for membrane fluidity and function.