Final answer:
Receptor-mediated endocytosis is the process of bringing larger substances into a cell through membrane invagination, membrane fusion, and vesicle formation.
Step-by-step explanation:
Receptor-mediated endocytosis is the process by which a cell responds to the binding of an extracellular substance with a receptor on its plasma membrane. This process involves membrane invagination, membrane fusion, and vesicle formation. It is used by cells to bring larger substances into the cell, and it is the best understood mechanism for this purpose.