Final answer:
A phospholipid is a type of lipid that forms a bilayer in a membrane structure, with hydrophobic tails facing inward and hydrophilic heads facing outward.
Step-by-step explanation:
A phospholipid is a type of lipid that contains a phosphate group. It consists of a hydrophilic (water-loving) head and a hydrophobic (water-fearing) tail. In a membrane structure, a bilayer of phospholipids forms the matrix, with the hydrophobic tails facing inward and the hydrophilic heads facing outward.